PLANT KINGDOM MCQs for NEET UG BIOLOGY — Hard, Page 3

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The pollination in Pinus is

View answer and explanation

Correct option: B

Anemophilous

Option B (Anemophilous) is correct because Pinus relies on wind for pollination, which is known as anemophily.

Solution approach

Correct Answer + Core Reason: Anemophilous. Pollination in Pinus occurs via wind, which is anemophilous.

Step-by-Step Solution:

Step 1: Define the different types of pollination.

Step 2: Recall the mode of pollination in Pinus.

Step 3: Pinus relies on wind for pollination, which is anemophilous.

Why other options are wrong:
- Option A: Entomophilous refers to pollination by insects, which is not the primary mode in Pinus.
- Option C: Hydrophilous refers to pollination by water, which is not the mode in Pinus.
- Option D: Malscophilous is not a recognized term for pollination types.

Key Concepts:
- Pollination types
- Anemophily
- Pinus reproduction

Memory Aids:
- *Anemo-* refers to *wind*, so anemophilous means wind pollination.

Quick Tips:
- Know the different types of pollination and the plants associated with each.

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Largest Unicellular algae is?

View answer and explanation

Correct option: C

Acetebularia

Option C (Acetebularia) is correct because Acetabularia is a genus of green algae known for being a large, single-celled organism, making it the largest unicellular algae.

Solution approach

Correct Answer + Core Reason: Acetebularia. It is the largest unicellular algae.

Step-by-Step Solution:

Step 1: Recall the different types of algae and their characteristics.

Step 2: Identify the largest unicellular algae.

Step 3: Acetabularia is the largest unicellular algae.

Why other options are wrong:
- Option A: Fucus is a multicellular brown alga.
- Option B: Coniferaceae is a family of cone-bearing trees, not algae.
- Option D: Rhodophyceae is a class of red algae, which are multicellular.

Key Concepts:
- Unicellular Algae: Algae consisting of a single cell.
- Acetabularia: A genus of large, unicellular green algae.

Memory Aids:
- Remember Acetabularia as a giant single cell.

Quick Tips:
- Associate Acetabularia with its large size and unicellular nature.

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Identify the pair of heterosporous pteridophytes among the following:

View answer and explanation

Correct option: D

Selaginella and Salvinia

Option D (Selaginella and Salvinia) is correct because both Selaginella (a pteridophyte) and Salvinia (an aquatic fern) produce two types of spores (microspores and megaspores), making them heterosporous.

Solution approach

Correct Answer + Core Reason: Selaginella and Salvinia. Both produce two types of spores.

Step-by-Step Solution:

Step 1: Define heterospory: Heterospory is the production of two different types of spores: microspores (which develop into male gametophytes) and megaspores (which develop into female gametophytes).

Step 2: Consider the given options and their spore production.

Step 3: Recognize that Selaginella is a well-known heterosporous pteridophyte.

Step 4: Identify Salvinia as another heterosporous pteridophyte (an aquatic fern).

Why other options are wrong:
- Option A: Psilotum and Salvinia: Psilotum is homosporous.
- Option B: Equisetum and Salvinia: Equisetum is homosporous.
- Option C: Lycopodium and Selaginella: Lycopodium is homosporous.

Key Concepts:
- Heterospory
- Microspores and megaspores
- Selaginella
- Salvinia
- Pteridophytes

Memory Aids:
- Remember that \"hetero\" means different, so heterosporous plants produce different types of spores.

Quick Tips:
- Know examples of heterosporous and homosporous pteridophytes.

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The correct statements about bryophytes are
I. the sperms are biflagellate
II. the sperms are released into water and fuses with the egg to produce the zygote out side the body
III. zygotes undergoes reduction division immediately
IV. they produce a multicellular body called a sporophyte

View answer and explanation

Correct option: C

I and IV

Option C (I and IV) is correct because bryophytes have biflagellate sperms and produce a multicellular sporophyte.

Solution approach

Correct Answer + Core Reason: C. I and IV. Bryophytes have biflagellate sperms, and the zygote develops into a multicellular sporophyte.

Step-by-Step Solution:

Step 1: Analyze Statement I: The sperms are biflagellate. This is correct for bryophytes.

Step 2: Analyze Statement II: The sperms are released into water and fuses with the egg to produce the zygote outside the body. Fertilization occurs inside the archegonium, not outside the body. This is incorrect.

Step 3: Analyze Statement III: Zygotes undergoes reduction division immediately. The zygote undergoes mitosis to form a sporophyte, which then undergoes meiosis. This is incorrect.

Step 4: Analyze Statement IV: They produce a multicellular body called a sporophyte. This is correct.

Why other options are wrong:
- Option A: I, II and III: Statements II and III are incorrect.
- Option B: I, II and IV: Statement II is incorrect.
- Option D: III and IV: Statement III is incorrect.

Key Concepts:
- Bryophytes
- Sperms
- Biflagellate
- Zygote
- Sporophyte
- Reduction division (meiosis)

Memory Aids:
- Bryophytes need water for fertilization.

Quick Tips:
- Review the life cycle of bryophytes.

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In which of the following group would you place a plant, which produce seeds but lacks fruits?

View answer and explanation

Correct option: D

Gymnosperms

Option D (Gymnosperms) is correct because gymnosperms are seed-producing plants that do not have fruits; their seeds are naked.

Solution approach

Correct Answer + Core Reason: Gymnosperms. Gymnosperms are seed-producing plants that lack fruits.

Step-by-Step Solution:

Step 1: Understand the question. The question asks for the group of plants that produce seeds but lack fruits.

Step 2: Consider the characteristics of each group.

Step 3: Fungi do not produce seeds.

Step 4: Pteridophytes do not produce seeds.

Step 5: Bryophytes do not produce seeds.

Step 6: Gymnosperms produce seeds but not fruits.

Step 7: Angiosperms produce both seeds and fruits.

Step 8: Conclusion: Gymnosperms fit the description.

Why other options are wrong:
- Option A: Fungi reproduce through spores, not seeds.
- Option B: Pteridophytes reproduce through spores, not seeds.
- Option C: Bryophytes reproduce through spores, not seeds.

Key Concepts:
- Plant classification
- Gymnosperms
- Angiosperms
- Seed production
- Fruit production

Memory Aids:
- Gymnosperms = Naked seeds

Quick Tips:
- Remember the key differences between plant groups based on their reproductive structures.

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Assertion: Adiantum caudatum is a walking fern.
Reason: Adiantum grows vegetatively by their leaf tips.

View answer and explanation

Correct option: A

If both the assertion and the reason are true and the reason is a correct explanation of the assertion

Option A (If both the assertion and the reason are true and the reason is a correct explanation of the assertion) is correct because Adiantum caudatum reproduces vegetatively through its leaf tips, making it a walking fern.

Solution approach

Correct Answer + Core Reason: If both the assertion and the reason are true and the reason is a correct explanation of the assertion. Adiantum caudatum is a walking fern because it grows vegetatively by their leaf tips.

Step-by-Step Solution:

Step 1: Recall the characteristics of Adiantum caudatum.

Step 2: Understand that it is a walking fern.

Step 3: Recognize that it reproduces vegetatively through its leaf tips.

Step 4: Understand that the reason correctly explains the assertion.

Why other options are wrong:
- Option B: The reason is a correct explanation of the assertion.
- Option C: The assertion is true.
- Option D: The assertion is true.

Key Concepts:
- Adiantum caudatum
- Walking fern
- Vegetative reproduction

Memory Aids:
- Walking fern = leaf tip propagation.

Quick Tips:
- Focus on the reproductive methods of ferns.

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Eutrophication is the result of

View answer and explanation

Correct option: B

Algae and aquatic plants

Option B (Algae and aquatic plants) is correct because eutrophication is primarily caused by the excessive enrichment of water bodies with nutrients, leading to increased growth of algae and aquatic plants.

Solution approach

Correct Answer + Core Reason: Algae and aquatic plants. Eutrophication is caused by excessive nutrient enrichment leading to algal blooms and increased aquatic plant growth.

Step-by-Step Solution:

Step 1: Define eutrophication: Eutrophication is the excessive enrichment of a water body with nutrients, typically nitrogen and phosphorus.

Step 2: Consider the effects of nutrient enrichment on aquatic organisms.

Step 3: Nutrient enrichment leads to increased growth of algae and aquatic plants, which can deplete oxygen levels and harm other aquatic life.

Why other options are wrong:
- Option A: Bryophyte: Bryophytes are terrestrial plants and do not directly cause eutrophication.
- Option C: Gymnosperm: Gymnosperms are terrestrial plants and do not directly cause eutrophication.
- Option D: Pteridophyte: Pteridophytes are terrestrial plants and do not directly cause eutrophication.

Key Concepts:
- Eutrophication
- Nutrient enrichment
- Algal blooms

Memory Aids:
- Eutrophication = Algae explosion

Quick Tips:
- Remember that eutrophication is caused by excessive nutrients in water.

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Terms artificial, natural and phylogenetic are related to types of

View answer and explanation

Correct option: D

Both (b) and (c )

Option D (Both (b) and (c )) is correct because the terms artificial, natural, and phylogenetic are used to describe different types of classifications for both plants and animals.

Solution approach

Correct Answer + Core Reason: Both (b) and (c ). These terms are related to the classification of both plants and animals.

Step-by-Step Solution:

Step 1: Understand the terms: artificial, natural, and phylogenetic.

Step 2: Artificial classification uses arbitrary characteristics.

Step 3: Natural classification uses overall similarities.

Step 4: Phylogenetic classification is based on evolutionary relationships.

Step 5: These types of classifications are applicable to both plants and animals.

Why other options are wrong:
- Option A: Cytotaxonomy is a specific type of classification based on chromosome characteristics, not a general term like the others.
- Option B: While true for plants, it's incomplete as it also applies to animals.
- Option C: While true for animals, it's incomplete as it also applies to plants.

Key Concepts:
- Artificial classification
- Natural classification
- Phylogenetic classification
- Plant classification
- Animal classification

Memory Aids:
- Artificial = Arbitrary
- Natural = Similarities
- Phylogenetic = Evolutionary

Quick Tips:
- Remember the basis of each type of classification.

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Algal zone is present in

View answer and explanation

Correct option: B

Coralloid root of Cycas

Option B (Coralloid root of Cycas) is correct because coralloid roots of Cycas harbor symbiotic cyanobacteria in the algal zone.

Solution approach

Correct Answer + Core Reason: Coralloid root of Cycas. The algal zone containing symbiotic cyanobacteria is found in the coralloid roots of Cycas.

Step-by-Step Solution:

Step 1: Recall the characteristics of Cycas roots.

Step 2: Understand the symbiotic relationship between Cycas and cyanobacteria.

Step 3: Identify the location of the algal zone within Cycas.

Step 4: Conclude that the algal zone is present in the coralloid roots.

Why other options are wrong:
- Option A: Normal roots of Cycas do not have a specialized algal zone.
- Option C: Pinus roots are associated with mycorrhizae, not cyanobacteria.
- Option D: The stem of Cycas does not have an algal zone.

Key Concepts:
- Symbiotic relationships
- Cyanobacteria
- Coralloid roots
- Cycas

Memory Aids:
- Coralloid roots = Cyanobacteria

Quick Tips:
- Remember that Cycas has specialized roots for nitrogen fixation.

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In which plant group gametophytic stage is main and sporophytic phase is subsidiary?

View answer and explanation

Correct option: C

Bryophyta

Option C (Bryophyta) is correct because bryophytes have a dominant gametophytic stage and a subsidiary sporophytic stage.

Solution approach

Correct Answer + Core Reason: Bryophyta. In bryophytes, the gametophyte is the dominant, independent phase, while the sporophyte is dependent on the gametophyte.

Step-by-Step Solution:

Step 1: The question asks about the plant group where the gametophytic stage is main and the sporophytic phase is subsidiary.

Step 2: Recall the life cycle patterns of different plant groups.

Step 3: Bryophytes (mosses, liverworts, and hornworts) have a dominant gametophyte and a dependent sporophyte.

Why other options are wrong:
- Option A: Pteridophyta (ferns) have a dominant sporophyte and an independent gametophyte.
- Option B: Gymnosperms have a dominant sporophyte and a reduced gametophyte.
- Option D: Angiosperms have a dominant sporophyte and a highly reduced gametophyte.

Key Concepts:
- Plant life cycles
- Alternation of generations
- Gametophyte and sporophyte

Memory Aids:
- Bryophytes = Big Gametophyte, Small Sporophyte

Quick Tips:
- Understand the life cycle patterns of different plant groups to answer such questions.

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Which kind of life-cycle pattern is exhibited by seed bearing plants?

View answer and explanation

Correct option: B

Diplontic

Option B (Diplontic) is correct because seed-bearing plants have a dominant diploid sporophyte and a reduced haploid gametophyte.

Solution approach

Correct Answer + Core Reason: Diplontic. Seed-bearing plants exhibit a diplontic life cycle where the diploid sporophyte is the dominant phase.

Step-by-Step Solution:

Step 1: Define the terms: Haplontic (haploid dominant), Diplontic (diploid dominant), Haplo-diplontic (both phases are multicellular and significant).

Step 2: Consider seed-bearing plants: The main plant body is the diploid sporophyte. The gametophyte is highly reduced and dependent on the sporophyte.

Step 3: Conclude: Since the diploid sporophyte is dominant, the life cycle is diplontic.

Why other options are wrong:
- Option A (Haplontic): This is incorrect because in haplontic life cycles, the haploid gametophyte is the dominant phase, which is not the case for seed-bearing plants.
- Option C (Haplo-diplontic): This is incorrect because while seed plants do have both haploid and diploid phases, the diploid phase is dominant, and the haploid phase is highly reduced and dependent.
- Option D (All of these): This is incorrect because only one life cycle type accurately describes seed-bearing plants.

Key Concepts:
- Life cycle patterns: Haplontic, Diplontic, Haplo-diplontic
- Sporophyte and Gametophyte generations
- Dominant phase in plant life cycles

Memory Aids:
- Diplontic = Diploid dominant
- Seed plants = Diplontic

Quick Tips:
- Remember the dominant phase for each life cycle type.

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Haploid brown, hairlike, delicate unicellular outgrowths are

View answer and explanation

Correct option: D

Rhizoids of fern plants

Option D (Rhizoids of fern plants) is correct because rhizoids are haploid, brown, hair-like, delicate unicellular outgrowths found in the gametophyte stage of fern plants.

Solution approach

Correct Answer + Core Reason: Rhizoids of fern plants. These are haploid, unicellular structures for anchorage.

Step-by-Step Solution:

Step 1: Recall the structure and function of rhizoids.

Step 2: Understand that rhizoids are root-like structures that anchor plants (especially non-vascular plants and the gametophytes of vascular plants) to a substrate.

Step 3: Recognize that rhizoids in fern gametophytes are typically haploid, brown, hair-like, and unicellular.

Why other options are wrong:
- Option A: Root hairs of gymnosperms: Root hairs are multicellular and found on the roots of sporophytes, not gametophytes.
- Option B: Paraphysis of mosses: Paraphyses are sterile filaments found among reproductive structures in bryophytes, not rhizoids.
- Option C: Root nodules of pulses: Root nodules contain nitrogen-fixing bacteria and are not hair-like outgrowths.

Key Concepts:
- Rhizoids
- Gametophyte
- Fern life cycle
- Root hairs
- Paraphysis
- Root nodules

Memory Aids:
- Think of rhizoids as the \"roots\" of the gametophyte.

Quick Tips:
- Know the difference between rhizoids and true roots.

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Majority of algae show external fertilization, except

View answer and explanation

Correct option: C

Spirogyra

Option C (Spirogyra) is correct because Spirogyra exhibits internal fertilization through conjugation, unlike the other algae listed which typically have external fertilization.

Solution approach

Correct Answer + Core Reason: Spirogyra. Spirogyra exhibits internal fertilization.

Step-by-Step Solution:

Step 1: Consider the fertilization methods in algae.

Step 2: External fertilization occurs outside the body, while internal fertilization occurs inside the body.

Step 3: Ulothrix, Ectocarpus, and Chlamydomonas typically exhibit external fertilization.

Step 4: Spirogyra exhibits internal fertilization through conjugation, where the gametes fuse inside the conjugation tube.

Why other options are wrong:
- Option A: Ulothrix: Ulothrix exhibits external fertilization.
- Option B: Ectocarpus: Ectocarpus exhibits external fertilization.
- Option D: Chlamydomonas: Chlamydomonas exhibits external fertilization.

Key Concepts:
- Fertilization in algae
- External vs. internal fertilization
- Conjugation in Spirogyra

Memory Aids:
- Spirogyra = Conjugation = Internal

Quick Tips:
- Remember that Spirogyra uses conjugation for reproduction.

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In gymnosperm, the multicellular female gametophyte is retained with in

View answer and explanation

Correct option: B

Megasporangium

Option B (Megasporangium) is correct because in gymnosperms, the multicellular female gametophyte is retained within the megasporangium.

Solution approach

Correct Answer + Core Reason: Megasporangium. The multicellular female gametophyte is retained within the megasporangium in gymnosperms.

Step-by-Step Solution:

Step 1: Understand the development of the female gametophyte in gymnosperms.

Step 2: Identify the structure that encloses and protects the female gametophyte.

Step 3: Recall that the megasporangium contains the developing female gametophyte.

Step 4: Conclude that the female gametophyte is retained within the megasporangium.

Why other options are wrong:
- Option A: Microsporangium contains the developing male gametophyte (pollen grains).
- Option C: Male gametophyte is the pollen grain.
- Option D: Archegonia are female sex organs within the gametophyte.

Key Concepts:
- Female gametophyte development
- Megasporangium
- Gymnosperms

Memory Aids:
- Mega = Female

Quick Tips:
- Remember the location and function of the megasporangium.

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Chloroplasts, with pyrenoid like structures are found in the leaves of

View answer and explanation

Correct option: A

Funaria

Option A (Funaria) is correct because Funaria, a moss, has chloroplasts with pyrenoid-like structures in its leaves, which are involved in carbon fixation.

Solution approach

Correct Answer + Core Reason: Funaria. Funaria has chloroplasts with pyrenoid-like structures in its leaves.

Step-by-Step Solution:

Step 1: Recall the characteristics of chloroplasts in different plant groups.

Step 2: Understand that Funaria, a moss, has chloroplasts with pyrenoid-like structures in its leaves.

Step 3: Pyrenoids are involved in carbon fixation.

Why other options are wrong:
- Option B: Cycas is a gymnosperm, and its leaves do not typically have prominent pyrenoid-like structures in their chloroplasts.
- Option C: Selaginella is a pteridophyte, and its leaves do not typically have prominent pyrenoid-like structures in their chloroplasts.
- Option D: Zea mays is an angiosperm, and its leaves do not typically have prominent pyrenoid-like structures in their chloroplasts.

Key Concepts:
- Chloroplasts
- Pyrenoids
- Funaria

Memory Aids:
- Remember that Funaria, a moss, has chloroplasts with pyrenoid-like structures.

Quick Tips:
- Focus on the presence of pyrenoid-like structures in Funaria's chloroplasts.

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Alternation of generations is not shown by

View answer and explanation

Correct option: D

1 and 2

Option D (1 and 2) is correct because Spirogyra (haplontic) and Fucus (diplontic) do not clearly show alternation of generations in the same way as haplo-diplontic plants.

Solution approach

Correct Answer + Core Reason: 1 and 2. Spirogyra and Fucus do not exhibit a clear alternation of generations in the same way as haplo-diplontic plants.

Step-by-Step Solution:

Step 1: Define alternation of generations: A life cycle in which both haploid (gametophyte) and diploid (sporophyte) multicellular stages occur.

Step 2: Consider the given options:
- Spirogyra: Haplontic life cycle (dominant haploid phase, zygotic meiosis).
- Fucus: Diplontic life cycle (dominant diploid phase, gametic meiosis).
- Marchantia: Haplo-diplontic life cycle (both phases are multicellular).

Step 3: Conclude: Spirogyra and Fucus do not show a distinct alternation of generations in the same way as Marchantia.

Why other options are wrong:
- Option A (Spirogyra): Spirogyra has a haplontic life cycle and does not show a clear alternation of generations.
- Option B (Fucus): Fucus has a diplontic life cycle and does not show a clear alternation of generations.
- Option C (Marchantia): Marchantia exhibits a haplo-diplontic life cycle and does show alternation of generations.

Key Concepts:
- Alternation of generations
- Haplontic, diplontic, and haplo-diplontic life cycles

Memory Aids:
- Haplontic and diplontic life cycles may not show a distinct alternation of generations.

Quick Tips:
- Remember the life cycle types for common organisms.

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[A]: Pteridophytes and Gymnosperms are included in Archegoniatae.

[R]: They have archegonia as female reproductive organ.

View answer and explanation

Correct option: A

Both A and R are true and R is the correct explanation of A

Option A (Both A and R are true and R is the correct explanation of A) is correct because both pteridophytes and gymnosperms possess archegonia as their female reproductive organs, placing them in the Archegoniatae.

Solution approach

Correct Answer + Core Reason: Both A and R are true and R is the correct explanation of A because both groups have archegonia.

Step-by-Step Solution:

Step 1: Evaluate the assertion: Pteridophytes and Gymnosperms are included in Archegoniatae. This is correct.

Step 2: Evaluate the reason: They have archegonia as female reproductive organ. This is also correct.

Step 3: Determine if the reason is a correct explanation of the assertion: The presence of archegonia is the defining characteristic of Archegoniatae, making the reason a correct explanation.

Why other options are wrong:
- Option B: R is the correct explanation of A.
- Option C: R is true.
- Option D: Both A and R are true.

Key Concepts:
- Archegoniatae
- Archegonia
- Pteridophytes and Gymnosperms

Memory Aids:
- Archegoniatae = plants with archegonia.

Quick Tips:
- Remember that archegonia are female sex organs found in bryophytes, pteridophytes, and gymnosperms.

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The most common type of spores produced in algae are motile, they are

View answer and explanation

Correct option: C

Zoospores

Option C (Zoospores) is correct because zoospores are motile spores produced by algae, equipped with flagella for movement.

Solution approach

Correct Answer + Core Reason: Zoospores. Zoospores are motile spores produced in algae.

Step-by-Step Solution:

Step 1: Define the different types of spores.
- Zoospores: Motile spores with flagella, produced by algae and some fungi.
- Sporangiospores: Non-motile spores produced within a sporangium.
- Conidia: Non-motile spores produced externally (not within a sporangium), often in chains.
- Chlamydospores: Thick-walled, non-motile resting spores.

Step 2: Identify the motile spore type.\nThe question specifies that the spores are motile. Zoospores are the only type of spore listed that are motile due to the presence of flagella.

Step 3: Conclusion.\nTherefore, the correct answer is Zoospores.

Why other options are wrong:
- Option A: Sporangiospores are non-motile.
- Option B: Conidia are non-motile.
- Option D: Chlamydospores are non-motile.

Key Concepts:
- Spore types in algae and fungi
- Motility of spores
- Zoospores

Memory Aids:
- Zoo- often refers to movement (e.g., zooplankton), so zoospores are motile.

Quick Tips:
- Know the different types of spores and their characteristics (motile vs. non-motile, method of production).

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Which one of the following pairs of plants are not seed producers?

View answer and explanation

Correct option: A

Fern and Funaria

Option A (Fern and Funaria) is correct because both ferns and Funaria (a moss) reproduce via spores and do not produce seeds.

Solution approach

Correct Answer + Core Reason: Fern and Funaria. Both ferns and Funaria (a moss) are spore-producing plants and do not produce seeds.

Step-by-Step Solution:

Step 1: Identify seed-producing plants.

Step 2: Ficus and Pinus are seed-producing plants.

Step 3: Ferns and Funaria are spore-producing plants.

Why other options are wrong:
- Option B: Funaria is a spore producer, but Ficus is a seed producer.
- Option C: Ficus is a seed producer, and Chlamydomonas is an algae (not a seed producer, but also not a pteridophyte or bryophyte).
- Option D: Fern is a spore producer, but Pinus is a seed producer.

Key Concepts:
- Seed production
- Spore production
- Plant classification

Memory Aids:
- Gymnosperms and Angiosperms = Seed producers
- Bryophytes and Pteridophytes = Spore producers

Quick Tips:
- Remember the major plant groups and their reproductive strategies.

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Assertion: Spirogyra shows haplontic life cycle.
Reason: Zygotic meiosis occurs in Spirogyra.

View answer and explanation

Correct option: A

If both assertion and reason are correct and the reason is a correct explanation of the assertion.

Option A is correct because Spirogyra does exhibit a haplontic life cycle, and this is due to the occurrence of zygotic meiosis, where the zygote is the only diploid cell and undergoes meiosis to produce haploid cells.

Solution approach

Correct Answer + Core Reason: If both assertion and reason are correct and the reason is a correct explanation of the assertion because Spirogyra has a haplontic life cycle due to zygotic meiosis.

Step-by-Step Solution:

Step 1: Understand the life cycle of Spirogyra.

Step 2: Assertion: Spirogyra shows haplontic life cycle. This is correct.

Step 3: Reason: Zygotic meiosis occurs in Spirogyra. This is also correct, and it explains why Spirogyra has a haplontic life cycle. The zygote undergoes meiosis, resulting in a dominant haploid phase.

Step 4: Therefore, the assertion and reason are correct, and the reason explains the assertion.

Why other options are wrong:
- Option B: The reason is a correct explanation.
- Option C: Both assertion and reason are correct.
- Option D: Both assertion and reason are correct.

Key Concepts:
- Haplontic life cycle
- Zygotic meiosis
- Spirogyra

Memory Aids:
- Haplontic: Zygotic meiosis.

Quick Tips:
- Remember that zygotic meiosis leads to a haplontic life cycle.

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Assertion: Selaginella and Salvinia are homosporous.
Reason: In Selaginella and Salvinia, similar kind of spores are produced.

View answer and explanation

Correct option: D

If both the assertion and reason are incorrect.

Option D (If both the assertion and reason are incorrect) is correct because Selaginella and Salvinia are heterosporous, not homosporous, and the reason is based on the incorrect assertion.

Solution approach

Correct Answer + Core Reason: Both the assertion and reason are incorrect because Selaginella and Salvinia are heterosporous.

Step-by-Step Solution:

Step 1: Evaluate the assertion: Selaginella and Salvinia are heterosporous, not homosporous. Therefore, the assertion is incorrect.

Step 2: Evaluate the reason: The reason states that similar kinds of spores are produced, which is consistent with homospory. Since the assertion is incorrect, the reason is also based on a false premise.

Step 3: Determine the correct option based on the evaluation of the assertion and reason.

Why other options are wrong:
- Option A: Both assertion and reason are not correct.
- Option B: Both assertion and reason are not correct.
- Option C: The assertion is not correct.

Key Concepts:
- Heterospory vs. Homospory
- Selaginella and Salvinia are heterosporous

Memory Aids:
- Remember that Selaginella and Salvinia are key examples of heterosporous plants.

Quick Tips:
- Carefully evaluate the assertion and reason independently before determining the relationship between them.

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Consider the following statements regarding reproduction in class-Chloropyceae.
I. Asexual reproduction is mainly by flagellated zoospores produced in zoosporangia.
II. The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous and oogamous.
Which of the statements given above are correct?

View answer and explanation

Correct option: C

I and II

Option C is correct because both statements accurately describe reproduction in Chlorophyceae: asexual reproduction via flagellated zoospores and sexual reproduction with isogamous, anisogamous, or oogamous methods.

Solution approach

Correct Answer + Core Reason: I and II because both statements accurately describe asexual and sexual reproduction in Chlorophyceae.

Step-by-Step Solution:

Step 1: Analyze each statement about reproduction in Chlorophyceae.

Step 2: I. Asexual reproduction is mainly by flagellated zoospores produced in zoosporangia. This is correct.

Step 3: II. The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous and oogamous. This is also correct.

Step 4: Therefore, both statements are correct.

Why other options are wrong:
- Option A: Statement II is also correct.
- Option B: Statement I is also correct.
- Option D: Both statements are correct.

Key Concepts:
- Reproduction in Chlorophyceae
- Asexual reproduction by zoospores
- Sexual reproduction (isogamous, anisogamous, oogamous)

Memory Aids:
- Chlorophyceae: Green algae; diverse reproduction methods.

Quick Tips:
- Remember the different modes of reproduction in algae.

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The leaves in pteridophytes are small as in

View answer and explanation

Correct option: C

Selaginella

Option C (Selaginella) is correct because Selaginella is a pteridophyte that exhibits small leaves (microphylls).

Solution approach

Correct Answer + Core Reason: Selaginella. Selaginella is a pteridophyte with small leaves (microphylls).

Step-by-Step Solution:

Step 1: Recall the characteristics of Volvox, Marsilia, Selaginella, and Azolla.

Step 2: Consider the leaf size in each plant. Selaginella has small leaves called microphylls.

Step 3: Conclusion: The leaves in pteridophytes are small as in Selaginella.

Why other options are wrong:
- Option A: Volvox is a green alga, not a pteridophyte.
- Option B: Marsilia has compound leaves, which are not considered small in the same way as Selaginella's microphylls.
- Option D: Azolla has small leaves, but Selaginella is a more classic example of microphyllous pteridophytes.

Key Concepts:
- Pteridophytes and their characteristics
- Microphylls vs. megaphylls

Memory Aids:
- Remember that Selaginella is a microphyllous pteridophyte.

Quick Tips:
- Differentiate between microphylls and megaphylls.

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What is the ratio of equational division that takes place in Cycas and angiosperms respectively during the formation of male gametes from pollen grains?

View answer and explanation

Correct option: C

2\mathrm{ }:\mathrm{ 1}

Option C (

2\mathrm{ }:\mathrm{ 1}

) is correct. Cycas requires two equational divisions, while angiosperms require one during male gamete formation from pollen grains.

Solution approach

Correct Answer + Core Reason: $2\mathrm{ }:\mathrm{ 1}$ . In Cycas, the pollen grain divides to form a generative cell and a tube cell. The generative cell then divides to form two male gametes. In angiosperms, the generative cell divides directly into two male gametes. Thus, the ratio is 2:1.

Step-by-Step Solution:

Step 1: Recall the process of male gamete formation in Cycas.

Step 2: Identify the number of equational divisions in Cycas: 2 (one to form generative and tube cell, and another to divide the generative cell).

Step 3: Recall the process of male gamete formation in angiosperms.

Step 4: Identify the number of equational divisions in angiosperms: 1 (to divide the generative cell).

Step 5: Calculate the ratio: 2:1.

Why other options are wrong:
- Option A: Incorrect ratio.
- Option B: Incorrect ratio.
- Option D: Incorrect ratio.

Key Concepts:
- Male gamete formation in Cycas
- Male gamete formation in angiosperms
- Equational division (mitosis)

Memory Aids:
- Cycas: 2 divisions, Angiosperms: 1 division

Quick Tips:
- Carefully count the number of mitotic divisions.

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Given below are two statements : One labelled as Assertion A and the other labelled as Reason R:

Assertion A : The first stage of gametophyte in the life cycle of moss is protonema stage.

Reason R : Protonema develops directly from spores produced in capsule.

In the light of the above statements, choose the most appropriate answer from options given below:

View answer and explanation

Correct option: C

Both A and R are correct and R is the correct explanation of A

Option C is correct because both the assertion and the reason are true, and the reason correctly explains why the protonema stage is the first stage of the gametophyte in mosses.

Solution approach

Correct Answer + Core Reason: Both A and R are correct and R is the correct explanation of A. The protonema is the first stage of the moss gametophyte, developing directly from spores.

Step-by-Step Solution:

Step 1: Understand the life cycle of mosses. The life cycle of mosses involves two main stages: the gametophyte and the sporophyte.

Step 2: Define protonema. Protonema is the first stage of the gametophyte, which is a thread-like structure.

Step 3: Understand the origin of protonema. Protonema develops directly from the spores produced in the capsule of the sporophyte.

Step 4: Relate the assertion and the reason. The assertion states that the first stage of the gametophyte is the protonema stage, and the reason states that the protonema develops directly from spores. The reason explains the assertion.

Why other options are wrong:
- Option A: This is incorrect because both the assertion and the reason are correct.
- Option B: This is incorrect because both the assertion and the reason are correct.
- Option D: This is incorrect because the reason is the correct explanation of the assertion.

Key Concepts:
- Moss life cycle
- Gametophyte and sporophyte stages
- Protonema development
- Spore formation

Memory Aids:
- Remember that spores give rise to protonema, which is the first stage of the gametophyte.

Quick Tips:
- When dealing with life cycles, always start with the spore stage and trace the development through different stages.

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Two very distinst generations are found in the life cycle of

View answer and explanation

Correct option: D

Ferns

Option D (Ferns) is correct because ferns exhibit a distinct alternation of generations, with both a prominent sporophyte and a gametophyte stage in their life cycle.

Solution approach

Correct Answer + Core Reason: Ferns. Ferns exhibit distinct sporophyte and gametophyte generations.

Step-by-Step Solution:

Step 1: Recall the life cycles of the given organisms.

Step 2: Identify which organism has two very distinct generations.

Step 3: Ferns have a distinct sporophyte and gametophyte generation.

Why other options are wrong:
- Option A: Bacteria reproduce primarily through binary fission and do not have distinct generations in the same way plants do.
- Option B: Spirogyra is an alga that primarily reproduces asexually, although it can undergo sexual reproduction, the generations are not as distinct as in ferns.
- Option C: Volvox is a colonial alga with a relatively simple life cycle compared to ferns.

Key Concepts:
- Alternation of Generations: The life cycle pattern in plants involving both haploid (gametophyte) and diploid (sporophyte) phases.
- Ferns: Pteridophytes with a distinct alternation of generations.

Memory Aids:
- Visualize the fern life cycle with both a visible sporophyte and a smaller gametophyte.

Quick Tips:
- Remember that ferns are a classic example of plants with alternation of generations.

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Calcium encrustation and larvicidal properties are present in

View answer and explanation

Correct option: A

Chara

Option A is correct because Chara is known for calcium encrustation on its thallus and has larvicidal properties.

Solution approach

Correct Answer + Core Reason: Chara. Chara exhibits calcium encrustation and has larvicidal properties.

Step-by-Step Solution:
Step 1: Recall the characteristics of Chara.
Step 2: Remember that Chara is known for calcium encrustation and its ability to kill mosquito larvae.

Why other options are wrong:
- Option B: Oscillatoria is a filamentous cyanobacterium, not known for calcium encrustation or larvicidal properties.
- Option C: Diatoms have silica in their cell walls, not calcium, and are not primarily known for larvicidal properties.
- Option D: Caulerpa is a green alga, but not known for calcium encrustation or larvicidal properties to the same extent as Chara.

Key Concepts:
- Chara characteristics
- Calcium encrustation
- Larvicidal properties

Memory Aids:
- Chara is \"charming\" because it kills larvae and has calcium.

Quick Tips:
- Know the unique characteristics of different algal genera.

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Which of these plants is correctly matched with its reproductive characteristics?

(i) Sphagnum: Male sex organs called antheridium produce biflagellate antherozoids while the female
sex organ called archegonium produces a single egg.

(ii) Sequoia: One of the megaspores enclosed within the megasporangium develops into a multicellular
female gametophyte that bears two or more archegonia or female sex organs.

(iii) Wolffia: One of the male gametes fuses with the egg cell to form a zygote while the other male
gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus.

(iv) Polysiphonia: Sexual reproduction is oogamous with non-motile gametes and accompanied by
complex post fertilization developments.

View answer and explanation

Correct option: D

i, ii, iii and iv

Option D (i, ii, iii and iv) is correct because all the statements accurately describe the reproductive characteristics of the given plants.

Solution approach

Correct Answer + Core Reason: D. i, ii, iii and iv. All the statements are correct regarding the reproductive characteristics of Sphagnum, Sequoia, Wolffia, and Polysiphonia.

Step-by-Step Solution:

Step 1: Analyze Statement i: Sphagnum: Male sex organs called antheridium produce biflagellate antherozoids while the female sex organ called archegonium produces a single egg. This is correct.

Step 2: Analyze Statement ii: Sequoia: One of the megaspores enclosed within the megasporangium develops into a multicellular female gametophyte that bears two or more archegonia or female sex organs. This is correct.

Step 3: Analyze Statement iii: Wolffia: One of the male gametes fuses with the egg cell to form a zygote while the other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus. This is correct.

Step 4: Analyze Statement iv: Polysiphonia: Sexual reproduction is oogamous with non-motile gametes and accompanied by complex post fertilization developments. This is correct.

Why other options are wrong:
- Option A: i and ii: Statements iii and iv are also correct.
- Option B: i, iii and iv: Statement ii is also correct.
- Option C: ii, iii and iv: Statement i is also correct.

Key Concepts:
- Sphagnum
- Sequoia
- Wolffia
- Polysiphonia
- Antheridium
- Archegonium
- Megaspore
- Oogamous
- Fertilization

Memory Aids:
- Remember the reproductive characteristics of each plant.

Quick Tips:
- Review the reproductive strategies of different plant groups.

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In which of the following, pyrenoids are present?

View answer and explanation

Correct option: C

Anthoceros

The correct answer is C (Anthoceros) because pyrenoids are characteristic features found within the chloroplasts of Anthoceros.

Solution approach

Correct Answer + Core Reason: Anthoceros. Pyrenoids are protein-containing structures found in the chloroplasts of certain algae and hornworts (like Anthoceros) that are involved in carbon fixation.

Step-by-Step Solution:

Step 1: Recall the characteristics of different bryophyte groups.

Step 2: Pyrenoids are associated with carbon fixation in algae and some bryophytes.

Step 3: Anthoceros is a hornwort known to contain pyrenoids within its chloroplasts.

Step 4: Marchantia and Riccia are liverworts and do not typically contain pyrenoids.

Why other options are wrong:
- Option A: Marchantia is a liverwort and does not contain pyrenoids.
- Option B: Riccia is a liverwort and does not contain pyrenoids.
- Option D: All of these is incorrect because only Anthoceros contains pyrenoids.

Key Concepts:
- Bryophytes
- Pyrenoids
- Anthoceros (hornwort)
- Marchantia and Riccia (liverworts)

Memory Aids:
- Remember that hornworts (Anthoceros) are unique among bryophytes for having pyrenoids.

Quick Tips:
- Focus on the specific characteristics that differentiate bryophyte groups.

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Seed habit is linked to

View answer and explanation

Correct option: B

Heterospory

Option B (Heterospory) is correct because heterospory, the production of two types of spores (microspores and megaspores), is a precursor to seed habit.

Solution approach

Correct Answer + Core Reason: Heterospory. Heterospory is the production of two types of spores (microspores and megaspores), a precursor to seed habit.

Step-by-Step Solution:

Step 1: Define seed habit.

Step 2: Define homospory and heterospory.

Step 3: Heterospory leads to the development of megaspores retained within the megasporangium, a key step toward seed formation.

Why other options are wrong:
- Option A: Homospory is the production of only one type of spore.
- Option C: Parthenogenesis is the development of an embryo without fertilization.
- Option D: Parthenocarpy is the development of fruit without fertilization.

Key Concepts:
- Seed habit
- Heterospory
- Homospory

Memory Aids:
- Hetero = Different spores, leads to seed habit

Quick Tips:
- Understand the evolutionary significance of heterospory.

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