Question

Assertion: Inbreeding increases homozygosity, exposing harmful recessive genes, some of which are eliminated by selection.
Reason: Continued inbreeding reduces fertility and productivity.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: Inbreeding refers to the mating between individuals that are related by ancestry and is more likely in populations that are, or have been, small. It can increase the chances of offspring being suffering from deleterious or recessive traits. Inbreeding can significantly influence organic phenomena which may prevent inbreeding depression. The two main negative consequences of inbreeding are an increased risk of undesirable genes and a discount in genetic diversity. Homozygosity refers to the possession of two identical alleles of a particular gene or genes by an organism.

Complete answer:
Option A: Both assertion and reason are correct but reason cannot justify the assertion because mating of closely related species will result in homozygosity recessive genes will get exposed which can increase the chances of offspring being suffering from deleterious or recessive traits. This leads to decreased biological fitness of the population and if continued, also reduces fertility and productivity.
So, option A is incorrect.
Option B: Both assertion and reason are correct and reason is not the correct explanation for assertion because when the offspring are produced by self fertilization or breeding between closely related parents it is called inbreeding. Inbreeding results in an increase in homozygosity. The most revealing impact of inbreeding is the loss of vigour and physiological efficiency of the organisms characterized by reduction in size. Loss of fitness within the progenies or decline in character expression with decreased heterozygosity arising from self mating is understood as inbreeding depression or inbreeding decline. Continued inbreeding reduces fertility and even productivity. But the inbreeding progeny with lethal and harmful recessive genes being homozygous express these traits which otherwise remain hidden in heterozygous individuals.
So, option B is correct.
Option C: Since assertion is a correct statement and reason statement is also correct.
So, option C is not correct.
Option D: Since Both assertion and reason statements are correct.
So, option D is not correct.

Hence, Option B is the correct answer.

Note:
Inbreeding is a technique used in selective breeding. The most revealing impact of inbreeding is the loss of vigour and physiological efficiency of the organisms characterized by reduction in size. Inbreeding increases the chances of acquiring deleterious traits. And later on, there would be more number of individuals with recessive alleles or alleles in homozygous condition. An individual that acquires deleterious traits from inbreeding is mentioned as an inbred.