Assertion & Reason Type Questions: Sexual Reproduction in Flowering Plants | Biology Class 12 - NEET PDF Download

Directions: In the following questions a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :

Question 1: 
Assertion (A): Flowers are structure of sexual reproduction.
Reason (R): Different type of embryological process occur inside the flower.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (a)
Sexual reproduction involves the transfer fusion of male and female gametes known as pollination. The fertilized ovules produce seeds that continue the next generation.

Question 2:
Assertion: Although geitonogamy is functionally cross-pollination involving a pollinating agent, genetically it is similar to autogamy since the pollen grains come from the same parent.
Reason: In getionogamy, pollen grains from the anthers of one flower are transferred to the stigma of another flower borne on the same plant.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (a)
Geitonogamy is a type of pollination in which pollen grains of one flower are transferred to the stigma of another flower belonging to either the same plant or genetically similar plant. It usually occurs in plants which show monoecious condition (unisexual male and female flowers borne on the same plant. Thus, geitonogamy is functionally cross pollination as it involves pollinating agent to carry out pollination, but genetically it is similar to autogamy (self-pollination) since the pollen grains come from the genetically same plant.

Question 3: 
Assertion (A): Entomophilous flowers are large, colourful, fragrant and rich in nectar.
Reason (R): If helps in attracting the pollinating agent.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (a)
Entomophily is a type of pollination, which is carried out by insects., Fragrance and colour of the flower's attract insects.

Question 4:
Assertion: Cleistogamous flowers produce assured seed set in the absence of pollinators.
Reason: These flowers do not open at all.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (a)
Cleistogamous flowers do not open at all thus ensuring fertilisation and hence produce assured seed-set even in the absence of pollinators.

Question 5:
Assertion (A): Tapetum is a part of anther wall that has 2-3 layers of cells.
Reason (R): Tapetum layers helps in development and growth of pollen grain.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (b)
In flowering plants, tapetum are the specialized cells that provide nutrition to the pollen grain within the anther.

Question 6:
Assertion: Autogamy is a transfer of pollen grains from an anther to the stigma of the same flower on the same plant.
Reason: Xenogamy is pollination between two flowers on different plants.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (c)
Based on the destination of pollen grains, two types of pollination are recognised. When pollen grains are transferred from an anther to the stigma of the same flower the process is called self-pollination or autogamy. Cross-pollination is further classified depending on whether the pollination has occurred between two flowers on the same plant (geitonogamy) or between two flowers on different plants (xenogamy).

Question 7: 

Assertion (A): Pea, bean, mustard are nonalbuminous seeds.

Reason (R): These seeds retain a part of endosperm as it is not completely used up during embryo development.

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (c)

Assertion is true but the reason is wrong, because in non-albuminous seeds, seeds does not retain any endosperm as it is completely used up during embryo development.

Question 8:
Assertion: Hydrophily is a major mode of pollination in most of the aquatic plants in angiosperms.
Reason: Almost all the aquatic dicot and monocot plants require water for the transport of male gametes and for fertilisation.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (d)
Hydrophily is the mode of pollination which is accomplished through the agency of water. Pollination by water is quite rare in flowering plants and is limited to only about 30 genera, mostly monocotyledons e.g., Vallisneria, Zostera, Ceratophyllum, etc. In many aquatic plants with emergent flowers, pollination occurs by wind or insects, e.g., Lotus, Water Lily, Water Hyacinth, etc.

Question 9:
Assertion (A): Seed is the final product of sexual reproduction in angiosperms.

Reason (R): A seed typically bears seed coat, cotyledons and an embryo axis.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (b)
After fertilization, the ovary wall develop in fruits embryo captured in the seed as final product of sexual reproduction in plants. The seed bear protective seed coat, cotyledons and embryo axis.

Question 10:
Assertion: Exine of a pollen grain is made up of sporopollenins which are resistant to high temperatures, strong acids or alkali as well as enzymatic degradation.
Reason: Sporopollenins are absent in the region of germ pores.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (b)
Wall of a pollen grain consists of two layers– outer exine and inner intine. Exine is the hard outer layer which is made up of sporopollenin. Sporopollenin is one of the most resistant organic material known. It can withstand high temperature, strong acids or alkali and is not degraded by enzymes. Because of the presence of sporopollenin, pollen grains are well preserved as fossils. At certain places, the exine is thin or absent, these areas may have thickened intine or deposition of callose. They are called germ pores (if rounded) or germinal furrows (if elongated). Sporopollenin is absent in the region of germ pores or germinal furrows.