Assertion. Protandry and protogyny ensure cross fertilization.
Reason . Cross fertilization introduces variation in progency.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

B

Explanation

Most of the animals have sex organs. They are either males or females. But in şome lower animals, the organs of both the sexes are found in the same individual. These are called bisexual or monoecious animals or hermaphrodites. In these animals, testes and ovaries do not mature simultaneously. For example in earthworm, testes mature earlier, while in others, e.g., sea-squirt, ovaries mature earlier, These conditions are respectively called protandry and protogyny. They ensure cross fertilization.Cross fertilization is a process in which gametes derived from different individuals are united to form zygote. It involves the mixing of two different genetic materials. This is better than self-fertilization as it introduces variation by combining traits of two individuals.