Sexual reproduction in flowering plants practice · Easy

Option A (Nucellus or integuments) is correct because adventive embryony involves embryos developing directly from somatic cells of the nucellus or integuments.

Option A (Chemotropism) is correct because the pollen tube's growth towards the ovule is guided by chemical signals.

Option C (Only B&C) is correct because both apomixis and cleistogamy assure seed set without the requirement of pollinators.

Option C (Nourish the developing pollen grains) is correct because the tapetum is the innermost layer of the anther and provides nutrients to the developing pollen grains.

Option D (Asexual reproduction) is correct because apomixis is a form of asexual reproduction that mimics sexual reproduction.

The correct answer is B (Homozygosity) because repeated selfing, or self-fertilization, leads to an increase in homozygosity as the same alleles are combined over generations.

Option C (Both (a) and (b)) is correct because both vegetative/asexual reproduction and apomixis involve a type of cell division that doesn't involve meiosis and result in offspring that are clones of the parent.

Option D (30 min) is correct because rice and wheat pollen grains lose viability within 30 minutes of their release.

The correct answer is B (Large, colourful, fragrant and rich in nectar) because insect-pollinated flowers typically have these characteristics to attract insects for pollination.

Option A (Both S-I and S-II are correct) is correct because unisexual flowers indeed have separate male and female reproductive organs, and both monoecious and dioecious plants bear such flowers.

Option C (Develops from unfertilized ovary) is correct because parthenocarpic fruits develop without fertilization, resulting in seedless fruits.

Option B (Has three celled egg apparatus) is correct because the egg apparatus consists of the egg cell and two synergid cells.

Option A (Never open) is correct because cleistogamous flowers are characterized by remaining closed, ensuring self-pollination.

Option D (Animals for pollination) is the correct answer because the majority of plants rely on animals as biotic agents for pollination.

The correct answer is C (Both (a) and (b)) because parthenocarpic fruits are indeed seedless, and parthenocarpy can be induced by hormones.

Option D (Central cell) is correct because the central cell is the largest cell in the embryo sac and contains two polar nuclei.

Option A (Sporopollenin) is correct because sporopollenin is a highly resistant polymer that protects pollen grains from degradation, allowing them to be preserved as fossils.

Option C (Both (a) and (b)) is correct because the pollen tube wall is composed of both cellulose and pectin.

Option C (ABB, AB) is correct because endosperm is formed by the fusion of two polar nuclei (BB) and one sperm (A), and the embryo is formed by the fusion of one sperm (A) and one egg (B).

Option D (Pollen wall has cavities containing proteins) is correct because while pollen walls do contain sporopollenin and are resistant to degradation, the statement that pollen walls have cavities containing proteins is generally true and not wrong.

Option C (Both (a) and (b)) is correct because the intine, the inner layer of the pollen grain wall, is composed of cellulose and pectin.

Option D (None of these) is correct because self-sterility, dichogamy, and heterogamy are all mechanisms that promote allogamy, but none are absolutely essential for it to occur.

Option B (Perform pollination) is correct because bees are crucial pollinators for many agricultural crops.

Option C (Geitonogamy) is correct because geitonogamy is the transfer of pollen from the anther of one flower to the stigma of another flower on the same plant.