Passes dorsoventrally to the anteroposterior axis of the body

A transverse section passing through the middle of the body

Passes along the length perpendicular to the dorsoventral axis of the body

ANIMAL KINGDOM MCQs for NEET UG BIOLOGY — Easy, Page 2

31 Easy

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Understanding +4 | -1

Which is a condition that in connected in the both external and internal structures and it is first found in which phylum of the animal kingdom

View answer and explanation

Correct option: D

Metamerism-Annelida

Option D (Metamerism-Annelida) is correct because metamerism, the segmentation of body structures, is a defining characteristic first prominently seen in the phylum Annelida.

Solution approach

Correct Answer + Core Reason: Metamerism-Annelida. Metamerism is segmentation, and it's a key feature of Annelids.

Step-by-Step Solution:

Step 1: Define the terms.

Step 2: Metamerism is the repetition of body segments.

Step 3: Annelida (segmented worms) exhibit true metamerism.

Step 4: Analyze the options.

Step 5: Option D correctly links metamerism to Annelida.

Why other options are wrong:
- Option A: Mutagenesis is the process of mutation, and Platyhelminthes (flatworms) are not primarily defined by this.
- Option B: Metagenesis is the alternation of generations, found in some Coelenterata (cnidarians), but not a defining characteristic connected to both external and internal structures.
- Option C: Appendages are a characteristic of Arthropoda, but it is not a condition connected in both external and internal structures like metamerism.

Key Concepts:
- Metamerism
- Annelida
- Segmentation
- Animal phyla

Memory Aids:
- Annelids: Think of \"annual rings\" representing segments.

Quick Tips:
- Know the defining characteristics of major animal phyla.

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Which animals belongs to the largest phylum and the second largest phylum of animalia respectively?

View answer and explanation

Correct option: B

Aedes and Loligo

Option B (Aedes and Loligo) is correct because Arthropoda is the largest phylum (Aedes is a mosquito, an arthropod) and Mollusca is the second largest (Loligo is a squid, a mollusk).

Solution approach

Correct Answer + Core Reason: Aedes and Loligo. Arthropoda is the largest phylum, and Mollusca is the second largest.

Step-by-Step Solution:

Step 1: Recall the largest and second largest phyla in the animal kingdom.

Step 2: The largest phylum is Arthropoda, and the second largest is Mollusca.

Step 3: Identify which animals belong to these phyla.

Step 4: Aedes (mosquito) belongs to Arthropoda, and Loligo (squid) belongs to Mollusca.

Why other options are wrong:
- Option A: Pila (snail) belongs to Mollusca, and Apis (honeybee) belongs to Arthropoda, but the order is reversed.
- Option C: Locusta (locust) belongs to Arthropoda, and Pheretima (earthworm) belongs to Annelida, which is not the second largest phylum.
- Option D: Nereis (clamworm) belongs to Annelida, and Octopus belongs to Mollusca, but Annelida is not the largest phylum.

Key Concepts:
- Animal classification
- Phylum Arthropoda
- Phylum Mollusca

Memory Aids:
- "Arthropods are the most numerous and Molluscs are next".

Quick Tips:
- Remember the major phyla and examples of animals belonging to each.

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The excretory cells, that are found in Platyhelminthes are

View answer and explanation

Correct option: D

All of these

Option D is correct because Protonephridia, flame cells, and solenocytes are all excretory cells found in Platyhelminthes.

Solution approach

Correct Answer + Core Reason: All of these. Protonephridia, flame cells, and solenocytes are all excretory cells found in Platyhelminthes.

Step-by-Step Solution:
Step 1: Recall the excretory structures in Platyhelminthes.
Step 2: Identify the different types of excretory cells: Protonephridia, flame cells, and solenocytes.
Step 3: Recognize that all these structures are found in Platyhelminthes.

Why other options are wrong:
- Option A: Protonephridia are excretory cells in Platyhelminthes, but not the only ones.
- Option B: Flame cells are excretory cells in Platyhelminthes, but not the only ones.
- Option C: Solenocytes are excretory cells in Platyhelminthes, but not the only ones.

Key Concepts:
- Excretory system in Platyhelminthes.
- Protonephridia, flame cells, and solenocytes.

Memory Aids:
- Remember that flame cells are a characteristic excretory structure in flatworms.

Quick Tips:
- Know the excretory structures of different animal phyla.

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Undifferentiated totipotent cells of sponges, are

View answer and explanation

Correct option: A

Archaeocytes

Option A (Archaeocytes) is correct because archaeocytes are undifferentiated totipotent cells in sponges that can transform into other specialized cell types.

Solution approach

Correct Answer + Core Reason: Archaeocytes. They are undifferentiated totipotent cells.

Step-by-Step Solution:

Step 1: Define each cell type in sponges.

Step 2: Archaeocytes - Totipotent cells that can differentiate into other cell types.

Step 3: Porocytes - Tubular cells that form pores in sponges.

Step 4: Trophocytes - Cells that transfer nutrients to other cells.

Step 5: Myocytes - Contractile cells around the osculum.

Step 6: Archaeocytes are the undifferentiated totipotent cells of sponges.

Why other options are wrong:
- Option B: Porocytes - These cells form pores, but are not totipotent.
- Option C: Trophocytes - These cells transfer nutrients, but are not totipotent.
- Option D: Myocytes - These cells are contractile, but are not totipotent.

Key Concepts:
- Sponge Cell Types
- Totipotency

Memory Aids:
- Archaeocytes: "Archaeo" suggests "ancient" or "original," implying they are the source of other cells.

Quick Tips:
- Remember the specific function of each cell type in sponges.

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Members of phylum-Porifera are

View answer and explanation

Correct option: D

Mostly marine animals but few are freshwater animals

Option D (Mostly marine animals but few are freshwater animals) is correct because the majority of Porifera species are found in marine environments, with a smaller number inhabiting freshwater habitats.

Solution approach

Correct Answer + Core Reason: Mostly marine animals but few are freshwater animals. Most sponges are marine, with some freshwater species.

Step-by-Step Solution:

Step 1: Consider the habitat of sponges.

Step 2: Sponges are predominantly marine animals.

Step 3: Some sponge species are found in freshwater environments.

Step 4: Therefore, most sponges are marine, but a few are freshwater animals.

Why other options are wrong:
- Option A: Exclusively marine animals - Incorrect, as some sponges are freshwater.
- Option B: Exclusively freshwater animals - Incorrect, as most sponges are marine.
- Option C: Mostly freshwater animals but few are marine animals - Incorrect, as the opposite is true.

Key Concepts:
- Sponge Habitat
- Marine vs. Freshwater Environments

Memory Aids:
- Think of the ocean when you think of sponges.

Quick Tips:
- Remember that while most sponges are marine, there are exceptions.

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True segmentation is also called

View answer and explanation

Correct option: C

Metamerism

Option C (Metamerism) is correct because true segmentation, where the body is divided into repeating segments, is also known as metamerism.

Solution approach

Correct Answer + Core Reason: Metamerism. True segmentation is also called metamerism.

Step-by-Step Solution:

Step 1: Understand the question. The question asks for the term that describes true segmentation.

Step 2: Define true segmentation. True segmentation (also called metamerism) is the serial repetition of similar body segments along the longitudinal axis of the body.

Step 3: Consider the other terms.

Step 4: Metagenesis is alternation of generations.

Step 5: Metamorphosis is a transformation or change.

Step 6: Conclusion: Metamerism is the correct term.

Why other options are wrong:
- Option A: Metagenesis is alternation of generations.
- Option B: Metamorphosis is a transformation or change.
- Option D: Metasegmerism is not a standard biological term.

Key Concepts:
- Segmentation
- Metamerism
- Metagenesis
- Metamorphosis

Memory Aids:
- Metamerism = Segments

Quick Tips:
- Remember the definition of metamerism.

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Which of the following statements is incorrect

View answer and explanation

Correct option: B

Water enter in sponge through osculum

Option B (Water enter in sponge through osculum) is correct because water enters a sponge through ostia (pores) and exits through the osculum.

Solution approach

Correct Answer + Core Reason: Water enter in sponge through osculum. Water enters through ostia, exits through osculum.

Step-by-Step Solution:

Step 1: Recall the characteristics of each statement.

Step 2: Hydra is a polyp.

Step 3: Water enters sponges through ostia (small pores) and exits through the osculum (large opening).

Step 4: Flatworms are triploblastic.

Step 5: Notochord is present in chordates.

Step 6: Therefore, the incorrect statement is that water enters in sponge through osculum.

Why other options are wrong:
- Option A: Hydra is indeed a polyp.
- Option C: Flatworms are triploblastic.
- Option D: Notochord is present in chordates.

Key Concepts:
- Sponge anatomy
- Hydra body form
- Triploblastic organization
- Notochord

Memory Aids:
- Ostia = In; Osculum = Out

Quick Tips:
- Remember the direction of water flow in sponges.

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A sagittal section

View answer and explanation

Correct option: D

A vertical section passing through the middle line of the body

Option D (A vertical section passing through the middle line of the body) is correct because a sagittal section divides the body into left and right halves along the midline.

Solution approach

Correct Answer + Core Reason: A vertical section passing through the middle line of the body. This is the definition of a sagittal section.

Step-by-Step Solution:

Step 1: Define the terms.

Step 2: A sagittal section is a plane that divides the body into left and right parts.

Step 3: A midsagittal section divides the body into equal left and right halves.

Step 4: Analyze the options.

Step 5: Option D accurately describes a sagittal section.

Why other options are wrong:
- Option A: Passes dorsoventrally to the anteroposterior axis of the body describes a transverse or horizontal section.
- Option B: A transverse section passing through the middle of the body describes a transverse section, not a sagittal section.
- Option C: Passes along the length perpendicular to the dorsoventral axis of the body describes a frontal or coronal section.

Key Concepts:
- Anatomical planes
- Sagittal section
- Transverse section
- Frontal section

Memory Aids:
- Sagittal: Think of an arrow (sagitta in Latin) splitting the body.

Quick Tips:
- Visualize the different anatomical planes.

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The characteristic larva of phylum-Coelenterata is

View answer and explanation

Correct option: A

Planula

Option A (Planula) is correct because the planula larva is the characteristic free-swimming larval stage of many cnidarians (Coelenterata).

Solution approach

Correct Answer + Core Reason: Planula. Planula is the characteristic larva of Coelenterata.

Step-by-Step Solution:

Step 1: Recall the life cycle of Coelenterates (Cnidaria).

Step 2: Identify the larval stage: The planula is a free-swimming, flattened, ciliated, bilaterally symmetric larval form.

Step 3: Consider other options:
- Cysticercus: A larval stage of tapeworms (Platyhelminthes).
- Rhabditiform: A type of nematode larva.
- Wriggler: A mosquito larva.

Step 4: Conclude that Planula is the characteristic larva of Coelenterata.

Why other options are wrong:
- Option B: Cysticercus is a larval stage of tapeworms, not coelenterates.
- Option C: Rhabditiform is a type of nematode larva, not coelenterates.
- Option D: Wriggler is a mosquito larva, not coelenterates.

Key Concepts:
- Animal development
- Larval stages
- Cnidarian life cycle

Memory Aids:
- Planula = Coelenterates

Quick Tips:
- Know the larval stages of common animal phyla.
- Associate Planula with Cnidaria.

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Water circulation in sponges does not help in

View answer and explanation

Correct option: A

Locomotion

Option A (Locomotion) is correct because sponges are sessile organisms and do not use water circulation for locomotion.

Solution approach

Correct Answer + Core Reason: Locomotion. Sponges are sessile and do not use water circulation for locomotion.

Step-by-Step Solution:
Step 1: Understand the functions of water circulation in sponges.
Step 2: Water circulation helps in food gathering, respiration (gas exchange), and removal of waste products.
Step 3: Sponges are sessile, meaning they are attached to a substrate and do not move around.

Why other options are wrong:
- Option A: Sponges do not use water circulation for locomotion.
- Option B: Sponges use water circulation for food gathering.
- Option C: Sponges use water circulation for respiration.
- Option D: Sponges use water circulation for removal of waste.

Key Concepts:
- Water circulation in sponges
- Sessile lifestyle

Memory Aids:
- Sponges = Sessile

Quick Tips:
- Remember the functions of water circulation in sponges.

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Analyzing +4 | -1

Select the option representing a wrong match in the given table.

View answer and explanation

Correct option: B

Animal-Adamsia, Characteristic-Polyp and medusa stage in life cycle , Taxon-Coelenterata

Option B (Animal-Adamsia, Characteristic-Polyp and medusa stage in life cycle , Taxon-Coelenterata) is correct because Adamsia (sea anemone) only exists in the polyp form, not both polyp and medusa.

Solution approach

Correct Answer + Core Reason: Animal-Adamsia, Characteristic-Polyp and medusa stage in life cycle , Taxon-Coelenterata. Adamsia only has the polyp stage.

Step-by-Step Solution:

Step 1: Analyze each option.

Step 2: (A) Animal-Macropus , Characteristic-Mammary glands, Taxon-Mammalia: Correct. Macropus (kangaroo) is a mammal with mammary glands.

Step 3: (B) Animal-Adamsia, Characteristic-Polyp and medusa stage in life cycle , Taxon-Coelenterata: Incorrect. Adamsia (sea anemone) only exists in the polyp form.

Step 4: (C) Animal-Anopheles, Characteristic-Malpighian tubules , Taxon-Arthropoda: Correct. Anopheles (mosquito) is an arthropod with Malpighian tubules.

Step 5: (D) Animal-Prawn , Characteristic-Gills , Taxon-Crustacea: Correct. Prawn is a crustacean with gills.

Why other options are wrong:
- Option A: Correct match.
- Option C: Correct match.
- Option D: Correct match.

Key Concepts:
- Animal classification
- Characteristics of different animal groups

Memory Aids:
- Remember that sea anemones are exclusively polyp forms.

Quick Tips:
- Know the life cycle stages of different coelenterates.

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Which of the following is true about sponges?

View answer and explanation

Correct option: C

Internal fertilization

Option C (Internal fertilization) is correct because sponges reproduce sexually with internal fertilization.

Solution approach

Correct Answer + Core Reason: Internal fertilization. Sponges reproduce sexually with internal fertilization.

Step-by-Step Solution:
Step 1: Recall the reproductive strategies of sponges.
Step 2: Sponges can reproduce asexually (fragmentation, budding, gemmules) and sexually.
Step 3: Sexual reproduction involves internal fertilization, where sperm fertilizes the egg inside the sponge.

Why other options are wrong:
- Option A: Sponges have intracellular digestion.
- Option B: Sponges have indirect development with a larval stage.
- Option C: Sponges have internal fertilization.
- Option D: Metagenesis is alternation of generations, not seen in sponges.

Key Concepts:
- Sponge reproduction: Asexual and Sexual
- Internal fertilization

Memory Aids:
- Sponges = Internal fertilization

Quick Tips:
- Remember the reproductive strategies of sponges.

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Which of the following is not true regarding phylum-Coelenterata?

View answer and explanation

Correct option: B

They have cellular level of organisation

Option B (They have cellular level of organisation) is correct because Coelenterata (Cnidaria) have a tissue level of organization, not a cellular level.

Solution approach

Correct Answer + Core Reason: They have cellular level of organisation. Coelenterates exhibit tissue level organization.

Step-by-Step Solution:

Step 1: Recall the levels of organization in animals.

Step 2: Cellular level of organization is found in Porifera (sponges).

Step 3: Coelenterates (Cnidaria) have tissue level of organization, with specialized cells forming tissues.

Step 4: Nematocytes are characteristic cells of Cnidaria.

Step 5: Coelenterates are diploblastic.

Step 6: The gastrovascular opening is called the hypostome.

Step 7: Therefore, the incorrect statement is that they have a cellular level of organization.

Why other options are wrong:
- Option A: Coelenterates are indeed diploblastic, having two germ layers.
- Option C: Nematocytes are characteristic of Cnidaria.
- Option D: The gastro-vascular opening is indeed called the hypostome.

Key Concepts:
- Levels of organization (cellular, tissue, organ, organ system)
- Diploblastic organization
- Nematocytes
- Cnidaria characteristics

Memory Aids:
- Porifera = Cellular
- Cnidaria = Tissue

Quick Tips:
- Remember the levels of organization associated with different phyla.

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Unique features of phylum-Ctenophora is

View answer and explanation

Correct option: B

Presence of comb plates only

Option B (Presence of comb plates only) is correct because Ctenophora are characterized by the presence of comb plates, which are used for locomotion.

Solution approach

Correct Answer + Core Reason: Presence of comb plates only. Ctenophores are defined by their comb plates.

Step-by-Step Solution:

Step 1: Identify the unique features of Ctenophora.

Step 2: Recall that Ctenophora, also known as comb jellies, possess comb plates (ctenes) used for swimming.

Step 3: Consider other features that might be present, but not unique to Ctenophora.

Step 4: Conclude that the presence of comb plates alone is the most unique characteristic.

Why other options are wrong:
- Option A: Presence of comb plates and comb jellies: While Ctenophora are comb jellies and have comb plates, the question asks for a *unique* feature. The name \"comb jellies\" isn't a unique feature in the same way the comb plates themselves are.
- Option C: Presence of tentacles only: Some Ctenophora have tentacles, but this is not a unique characteristic as other phyla also possess tentacles.
- Option D: Alteration of generation only: Alteration of generation is not a characteristic feature of Ctenophora.

Key Concepts:
- Characteristics of Phylum Ctenophora
- Comb plates (ctenes)

Memory Aids:
- Ctenophora = Comb-bearing (ctenes)

Quick Tips:
- Focus on the most defining and unique characteristic when answering such questions.

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Differentiated embryonic layers are called
I. ectoderm II. Endoderm
III. Mesoderm III. Mesoglea

View answer and explanation

Correct option: B

I, II and III

Option B (I, II and III) is correct because ectoderm, endoderm, and mesoderm are the three primary germ layers that differentiate during embryonic development.

Solution approach

Correct Answer + Core Reason: I, II and III. Ectoderm, Endoderm and Mesoderm are the three differentiated embryonic layers.

Step-by-Step Solution:

Step 1: Understand the question. The question asks which of the listed layers are differentiated embryonic layers.

Step 2: Recall the three germ layers: ectoderm, mesoderm, and endoderm.

Step 3: Ectoderm: The outermost layer, gives rise to the epidermis and nervous system.

Step 4: Endoderm: The innermost layer, gives rise to the lining of the digestive tract and associated organs.

Step 5: Mesoderm: The middle layer, gives rise to muscles, bones, and circulatory system.

Step 6: Mesoglea: A non-cellular jelly-like substance found between the ectoderm and endoderm in cnidarians and sponges.

Step 7: Conclusion: Ectoderm, endoderm, and mesoderm are the differentiated embryonic layers.

Why other options are wrong:
- Option A: Mesoglea is not a differentiated embryonic layer; it is a non-cellular substance.
- Option C: Mesoglea is not a differentiated embryonic layer; it is a non-cellular substance.
- Option D: Mesoglea is not a differentiated embryonic layer; it is a non-cellular substance.

Key Concepts:
- Germ layers (ectoderm, mesoderm, endoderm)
- Embryonic development

Memory Aids:
- Ectoderm = Outer
- Endoderm = Inner
- Mesoderm = Middle

Quick Tips:
- Remember the derivatives of each germ layer.

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Which of the following phyla are schizocoelomates?

View answer and explanation

Correct option: B

Annelida, Arthropoda and Mollusca

Option B (Annelida, Arthropoda and Mollusca) is correct because schizocoelomates are animals in which the coelom is formed by splitting of the mesodermal embryonic tissue, and this occurs in Annelida, Arthropoda, and Mollusca.

Solution approach

Correct Answer + Core Reason: Annelida, Arthropoda and Mollusca. Schizocoelomates form the coelom by splitting of mesoderm.

Step-by-Step Solution:

Step 1: Understand the term schizocoelomate. Schizocoelomates are animals in which the coelom (body cavity) is formed by the splitting of the mesoderm during embryonic development.

Step 2: Consider the coelom formation in each phylum.

Step 3: Annelida: Schizocoelomate.

Step 4: Arthropoda: Schizocoelomate.

Step 5: Mollusca: Schizocoelomate.

Step 6: Platyhelminthes: Acoelomate (no coelom).

Step 7: Aschelminthes: Pseudocoelomate (false coelom).

Step 8: Conclusion: Annelida, Arthropoda, and Mollusca are schizocoelomates.

Why other options are wrong:
- Option A: Platyhelminthes are acoelomates.
- Option C: Platyhelminthes are acoelomates and Aschelminthes are pseudocoelomates.
- Option D: Aschelminthes are pseudocoelomates.

Key Concepts:
- Coelom formation
- Schizocoelomate
- Acoelomate
- Pseudocoelomate
- Animal classification

Memory Aids:
- Schizo = Split (mesoderm)

Quick Tips:
- Remember the different types of coelom formation.

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Which of the following shows polymorphism?

View answer and explanation

Correct option: A

Physalia

Option A (Physalia) is correct because Physalia, the Portuguese man-of-war, exhibits polymorphism, with different individuals specialized for different functions (feeding, reproduction, defense).

Solution approach

Correct Answer + Core Reason: Physalia. Physalia exhibits polymorphism.

Step-by-Step Solution:

Step 1: Define polymorphism: The occurrence of different forms or castes within a species, each specialized for a particular function.

Step 2: Consider Physalia: Physalia (Portuguese man-of-war) is a colonial cnidarian with different zooids specialized for different functions (e.g., pneumatophore, gastrozooids, gonozooids, dactylozooids).

Step 3: Consider other options:
- Trypanosoma: A parasitic protozoan; does not exhibit polymorphism in the same way.
- Termite: While termites have castes, the degree of polymorphism is not as high as in Physalia.

Step 4: Conclude that Physalia shows the most pronounced polymorphism.

Why other options are wrong:
- Option B: Trypanosoma is a parasitic protozoan and does not exhibit polymorphism in the same way as Physalia.
- Option C: Termites have castes, but the degree of polymorphism is not as high as in Physalia.
- Option D: Only Physalia exhibits polymorphism to a high degree.

Key Concepts:
- Polymorphism
- Cnidarian biology
- Colonial organisms

Memory Aids:
- Physalia = Portuguese man-of-war = Polymorphism

Quick Tips:
- Remember that Physalia is a colonial organism with specialized zooids.
- Associate polymorphism with specialized functions within a colony.

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Analyzing +4 | -1

Among Aedes, Limulus, Pheretima, Ancylostoma, Antedon, how many possess true coelom, segmentation and closed circulatory system?

View answer and explanation

Correct option: A

One

Option A (One) is correct. Only Pheretima (earthworm) possesses true coelom, segmentation, and a closed circulatory system among the listed organisms.

Solution approach

Correct Answer + Core Reason: One. Pheretima is the only organism with all three characteristics.

Step-by-Step Solution:

Step 1: Analyze each organism for the presence of true coelom, segmentation, and closed circulatory system.

Step 2: Aedes (mosquito) - Arthropoda, has coelom reduced (hemocoel), segmentation, and open circulatory system.

Step 3: Limulus (horseshoe crab) - Arthropoda, has coelom reduced (hemocoel), segmentation, and open circulatory system.

Step 4: Pheretima (earthworm) - Annelida, has true coelom, segmentation, and closed circulatory system.

Step 5: Ancylostoma (hookworm) - Aschelminthes, has pseudocoelom, no true segmentation, and open circulatory system.

Step 6: Antedon (feather star) - Echinodermata, has true coelom, no segmentation, and open circulatory system (reduced).

Step 7: Only Pheretima possesses all three characteristics.

Why other options are wrong:
- Option B: Two - Incorrect, as only one organism fits the criteria.
- Option C: Three - Incorrect, as only one organism fits the criteria.
- Option D: Four - Incorrect, as only one organism fits the criteria.

Key Concepts:
- Animal Kingdom Classification
- Coelom types (true coelom, pseudocoelom, hemocoel)
- Segmentation (metamerism)
- Circulatory system types (open, closed)

Memory Aids:
- Annelids (like earthworms) are segmented worms with a closed circulatory system and a true coelom.

Quick Tips:
- Remember the key characteristics of major phyla to quickly identify organisms.

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Asymmetrical animals are

View answer and explanation

Correct option: D

All of these

Option D (All of these) is correct because Amoeba, Spongilla, and Spongia are all asymmetrical animals, meaning they lack a defined symmetry.

Solution approach

Correct Answer + Core Reason: All of these. Amoeba, Spongilla and Spongia are all asymmetrical animals.

Step-by-Step Solution:

Step 1: Understand the question. The question asks which of the listed animals are asymmetrical.

Step 2: Define asymmetry. Asymmetry means lacking a defined symmetry; the body cannot be divided into equal halves.

Step 3: Consider each animal.

Step 4: Amoeba: Unicellular and asymmetrical.

Step 5: Spongilla: A freshwater sponge, typically asymmetrical.

Step 6: Spongia: A marine sponge, typically asymmetrical.

Step 7: Conclusion: All three are asymmetrical.

Why other options are wrong:
- Option A: Amoeba is only one of the asymmetrical animals.
- Option B: Spongilla is only one of the asymmetrical animals.
- Option C: Spongia is only one of the asymmetrical animals.

Key Concepts:
- Symmetry (asymmetry, radial, bilateral)
- Animal classification

Memory Aids:
- Asymmetry = No symmetry

Quick Tips:
- Remember the different types of symmetry in animals.

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Triploblastic animal differ from diploblstic animal by having

View answer and explanation

Correct option: B

Mesoderm

Option B (Mesoderm) is correct because triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm), while diploblastic animals have only two (ectoderm and endoderm).

Solution approach

Correct Answer + Core Reason: Mesoderm. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm), while diploblastic animals have only ectoderm and endoderm.

Step-by-Step Solution:
Step 1: Define diploblastic and triploblastic organization.
Step 2: Diploblastic: Two germ layers (ectoderm and endoderm).
Step 3: Triploblastic: Three germ layers (ectoderm, mesoderm, and endoderm).
Step 4: The key difference is the presence of the mesoderm in triploblastic animals.

Why other options are wrong:
- Option A: Ectoderm is present in both diploblastic and triploblastic animals.
- Option B: Mesoderm is present only in triploblastic animals.
- Option C: Endoderm is present in both diploblastic and triploblastic animals.
- Option D: All of these is incorrect since only mesoderm differentiates them.

Key Concepts:
- Germ layers: Ectoderm, Mesoderm, Endoderm
- Diploblastic vs. Triploblastic organization

Memory Aids:
- Tri = Three layers (Ecto, Meso, Endo)

Quick Tips:
- Remember which animals are diploblastic and triploblastic.

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Characteristic of coelenterate is occurrence of

View answer and explanation

Correct option: A

Nematocysts

Option A (Nematocysts) is correct because Nematocysts are stinging cells that are a defining characteristic of the phylum Coelenterata (Cnidaria).

Solution approach

Correct Answer + Core Reason: Nematocysts. Nematocysts are the stinging cells characteristic of coelenterates.

Step-by-Step Solution:

Step 1: Recall the characteristics of Coelenterates (Cnidaria).

Step 2: Remember that Cnidarians possess specialized cells called cnidocytes, which contain nematocysts (stinging organelles).

Step 3: Consider other features that might be present in some Cnidarians, but are not defining characteristics.

Step 4: Conclude that the presence of nematocysts is the most characteristic feature of Coelenterates.

Why other options are wrong:
- Option B: Polymorphism: While some Cnidarians exhibit polymorphism (different body forms), it is not a universal characteristic of the phylum.
- Option C: Flame cells: Flame cells are excretory structures found in Platyhelminthes (flatworms), not Cnidarians.
- Option D: Choanocytes: Choanocytes are flagellated collar cells found in Porifera (sponges), not Cnidarians.

Key Concepts:
- Characteristics of Phylum Cnidaria (Coelenterata)
- Nematocysts (stinging cells)
- Cnidocytes

Memory Aids:
- Cnidarians = Nema-tocysts (stinging cells)

Quick Tips:
- Focus on the defining characteristics when answering questions about animal phyla.

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Identify the incorrect statement.

View answer and explanation

Correct option: D

In unicellular organisms, all physiological functions are performed by multiple or group of cells

Option D (In unicellular organisms, all physiological functions are performed by multiple or group of cells) is correct because in unicellular organisms, all physiological functions are performed by a single cell, not multiple or a group of cells.

Solution approach

Correct Answer + Core Reason: In unicellular organisms, all physiological functions are performed by multiple or group of cells. This statement is incorrect because unicellular organisms perform all functions within a single cell.

Step-by-Step Solution:

Step 1: Understand the organization of life, from cells to organ systems.

Step 2: Recall the characteristics of unicellular organisms.

Step 3: Recognize that unicellular organisms perform all functions within a single cell.

Why other options are wrong:
- Option A: Tissues are organized in specific proportion and pattern to form an organ like stomach, lung, heart and kidney - This statement is correct.
- Option B: Cells, tissues, organs and organ systems split up the work in a way that exhibits division of labour - This statement is correct.
- Option C: The human body is composed of billions of cells to perform various functions - This statement is correct.

Key Concepts:
- Levels of organization in living organisms
- Unicellular organisms
- Division of labor

Memory Aids:
- Remember that \'uni-\' means \'one,\' so unicellular organisms have only one cell.

Quick Tips:
- Know the basic characteristics of different levels of biological organization.

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Read the following statements
a) Metagenesis is observed in Helminths.
b) Echinoderms are triploblastic and coelomate animals.
c) Round worms have organ-system level of body organization.
d) Comb plates present in ctenophores help in digestion.
e) Water vascular system is characteristic of Echinoderms.
Choose the correct answer from the options given below.

View answer and explanation

Correct option: B

(b), (c) and (e) are correct

Option B is correct because Echinoderms are triploblastic and coelomate, roundworms have organ-system level organization, and echinoderms possess a water vascular system.

Solution approach

Correct Answer + Core Reason: (b), (c) and (e) are correct. These statements accurately describe characteristics of Echinoderms and Roundworms.

Step-by-Step Solution:

Step 1: Evaluate each statement individually.

Step 2: Statement a) Metagenesis is observed in Helminths: Incorrect. Metagenesis is observed in cnidarians (e.g., Obelia).

Step 3: Statement b) Echinoderms are triploblastic and coelomate animals: Correct.

Step 4: Statement c) Round worms have organ-system level of body organization: Correct.

Step 5: Statement d) Comb plates present in ctenophores help in digestion: Incorrect. Comb plates help in locomotion.

Step 6: Statement e) Water vascular system is characteristic of Echinoderms: Correct.

Why other options are wrong:
- Option A: Includes incorrect statements (a) and (d).
- Option C: Includes incorrect statement (d).
- Option D: Includes incorrect statement (a).

Key Concepts:
- Metagenesis
- Triploblastic and coelomate animals
- Organ-system level of organization
- Comb plates in ctenophores
- Water vascular system in echinoderms

Memory Aids:
- "Echinoderms have a unique water vascular system".

Quick Tips:
- Carefully analyze each statement and eliminate options containing false statements.

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Find the odd one out

View answer and explanation

Correct option: D

Sea horse

Option D (Sea horse) is the odd one out because it is a fish, while the others are cnidarians.

Solution approach

Correct Answer + Core Reason: Sea horse. It is a fish, while the others are cnidarians.

Step-by-Step Solution:

Step 1: Identify the phylum of each organism.

Step 2: Sea fan - Cnidaria

Step 3: Sea pen - Cnidaria

Step 4: Sea cucumber - Echinodermata

Step 5: Sea horse - Chordata (fish)

Step 6: Sea fan and Sea pen belong to the phylum Cnidaria. Sea cucumber belongs to phylum Echinodermata. Sea horse belongs to phylum Chordata.

Step 7: Sea horse is the odd one out because it is a fish, while the others are invertebrates, and sea fan and sea pen are cnidarians.

Why other options are wrong:
- Option A: Sea fan - It is a cnidarian, similar to sea pen.
- Option B: Sea pen - It is a cnidarian, similar to sea fan.
- Option C: Sea cucumber - It is an echinoderm, but sea horse is more distantly related.

Key Concepts:
- Animal Kingdom Classification
- Phylum Cnidaria
- Phylum Chordata
- Phylum Echinodermata

Memory Aids:
- Remember the general characteristics of each phylum.

Quick Tips:
- Group organisms based on their phylum to find the odd one out.

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Classification of sponges is primarily based on the

View answer and explanation

Correct option: C

Skeleton

Option C (Skeleton) is correct because the classification of sponges is primarily based on the type of skeletal elements (spicules) they possess.

Solution approach

Correct Answer + Core Reason: Skeleton. Sponge classification is based on the type of spicules.

Step-by-Step Solution:

Step 1: Consider the basis for sponge classification.

Step 2: Sponge classification is primarily based on the type of skeletal elements (spicules) present.

Step 3: Spicules can be made of calcium carbonate, silica, or spongin fibers.

Step 4: The type and arrangement of spicules are used to classify sponges into different classes.

Why other options are wrong:
- Option A: Body organization - While body organization is important, it is not the primary basis for classification.
- Option B: Body plan - While body plan is important, it is not the primary basis for classification.
- Option D: Canal system - While the canal system is important, it is not the primary basis for classification.

Key Concepts:
- Sponge Classification
- Spicules

Memory Aids:
- Remember that spicules are key to sponge classification.

Quick Tips:
- Focus on the skeletal elements when classifying sponges.

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Which of the following phylum or class exhibit the presence of a notochord?

View answer and explanation

Correct option: C

Fishes

Option C (Fishes) is correct because fishes belong to the phylum Chordata, which is characterized by the presence of a notochord at some stage in their development.

Solution approach

Correct Answer + Core Reason: Fishes. Fishes are chordates, and chordates are defined by the presence of a notochord.

Step-by-Step Solution:

Step 1: Recall the definition of Chordata. A key characteristic of chordates is the presence of a notochord, a flexible rod-like structure that supports the body.

Step 2: Consider each option:
- Arthropods: Do not have a notochord; they have an exoskeleton.
- Echinodermata: Have a water vascular system and radial symmetry, but no notochord as adults.
- Fishes: Possess a notochord (at least during embryonic development).
- Porifera: Are sponges and lack true tissues and organs, including a notochord.

Step 3: Determine the correct answer. Only fishes belong to the phylum Chordata and therefore exhibit a notochord.

Why other options are wrong:
- Option A: Arthropods: Arthropods are characterized by an exoskeleton and jointed appendages; they lack a notochord.
- Option B: Echinodermata: Adult echinoderms have radial symmetry and a water vascular system, but they do not possess a notochord.
- Option D: Porifera: Porifera are sponges, which are the most primitive animals and lack a notochord.

Key Concepts:
- Notochord
- Phylum Chordata
- Animal Classification

Memory Aids:
- Chordata: Think "cord" (notochord).

Quick Tips:
- Remember the defining characteristics of each phylum to quickly eliminate incorrect options.

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Choose the correct match

View answer and explanation

Correct option: A

Porifera – A symmetrical

Option A (Porifera – A symmetrical) is correct because Porifera are generally asymmetrical organisms.

Solution approach

Correct Answer + Core Reason: Porifera – A symmetrical. Porifera lack a defined symmetry, hence they are asymmetrical.

Step-by-Step Solution:

Step 1: Identify the characteristics of Porifera.

Step 2: Recall that Porifera are the sponges, which are the simplest multicellular animals.

Step 3: Understand that sponges generally lack any form of symmetry, making them asymmetrical.

Step 4: Therefore, the correct match is Porifera - A symmetrical.

Why other options are wrong:
- Option B: Coelenterates exhibit radial symmetry, not bilateral.
- Option C: Chordates exhibit bilateral symmetry, not radial.
- Option D: Annelida exhibit organ system level of organization, not tissue level.

Key Concepts:
- Symmetry in animals
- Characteristics of Porifera, Coelenterata, Chordata, and Annelida
- Levels of organization in animals

Memory Aids:
- Remember that \"sponges are simple and asymmetrical.\"

Quick Tips:
- Review the characteristics and symmetry of different animal phyla.

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Which of the following is wrongly matched?

View answer and explanation

Correct option: B

Annelida – Hydra

Option B (Annelida – Hydra) is correct because Hydra belongs to the phylum Cnidaria, not Annelida. Annelida consists of segmented worms.

Solution approach

Correct Answer + Core Reason: Annelida – Hydra. Hydra belongs to Cnidaria, not Annelida.

Step-by-Step Solution:

Step 1: Recall the characteristics of each phylum listed: Arthropoda, Annelida, Echinodermata, and Nemathelminthes.

Step 2: Identify the organisms that belong to each phylum.

Step 3: Recognize that Hydra is a cnidarian, not an annelid.

Why other options are wrong:
- Option A: Arthropoda – Cockroach is a correct match.
- Option C: Echinodermata – Star fish is a correct match.
- Option D: Nemathelminthes – Ascaris is a correct match.

Key Concepts:
- Animal classification
- Phylum characteristics

Memory Aids:
- Remember that annelids are segmented worms, and Hydra is a simple, tubular organism.

Quick Tips:
- Know the key characteristics and representative organisms of each major animal phylum.

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Body cavity lined by mesoderm is called

View answer and explanation

Correct option: C

Coelom

Option C (Coelom) is correct because the coelom is defined as a body cavity that is lined by mesoderm.

Solution approach

Correct Answer + Core Reason: Coelom. The coelom is a body cavity lined by mesoderm.

Step-by-Step Solution:

Step 1: Understand the question. The question asks for the term for a body cavity lined by mesoderm.

Step 2: Define coelom. A coelom is a body cavity located between the intestinal canal and the body wall. It is lined by mesoderm.

Step 3: Consider the other terms.

Step 4: Coelenteron is the digestive cavity of cnidarians.

Step 5: Pseudocoel is a body cavity not completely lined by mesoderm.

Step 6: Blastocoel is the fluid-filled cavity of a blastula.

Step 7: Conclusion: Coelom is the correct term.

Why other options are wrong:
- Option A: Coelenteron is the digestive cavity of cnidarians.
- Option B: Pseudocoel is not completely lined by mesoderm.
- Option D: Blastocoel is the cavity of a blastula.

Key Concepts:
- Coelom
- Pseudocoel
- Acoelomate
- Body cavities

Memory Aids:
- Coelom = Mesoderm lining

Quick Tips:
- Remember the different types of body cavities and their linings.

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The animal with bilateral symmetry in young stage, and radial pentamerous symmetry in the adult stage belongs to the phylum

View answer and explanation

Correct option: D

Echinodermata

Option D (Echinodermata) is correct because echinoderms have bilateral symmetry in their larval stage and radial pentamerous symmetry as adults.

Solution approach

Correct Answer + Core Reason: Echinodermata. Echinoderms exhibit bilateral symmetry in the larval stage and radial pentamerous symmetry in the adult stage.

Step-by-Step Solution:

Step 1: Recall the symmetry characteristics of different animal phyla.

Step 2: Analyze the options:
- A. Annelida: Bilateral symmetry throughout their life cycle.
- B. Mollusca: Bilateral symmetry throughout their life cycle.
- C. Cnidaria: Radial symmetry throughout their life cycle.
- D. Echinodermata: Larvae are bilaterally symmetrical, while adults exhibit radial pentamerous symmetry (five-part radial symmetry).

Step 3: Conclusion: Echinodermata is the only phylum that fits the description.

Why other options are wrong:
- Option A: Annelida maintain bilateral symmetry throughout their life cycle.
- Option B: Mollusca maintain bilateral symmetry throughout their life cycle.
- Option C: Cnidaria exhibit radial symmetry throughout their life cycle.

Key Concepts:
- Animal Symmetry: Bilateral, Radial
- Echinodermata characteristics
- Animal Development

Memory Aids:
- Remember that Echinoderms are unique in having a shift from bilateral to radial symmetry during development.

Quick Tips:
- Know the symmetry characteristics of each major animal phylum, including any developmental changes.

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