Question

Assertion (A): ‘XX-XY’ type of sex-determination mechanism is an example of male heterogamety.

Reason (R): In birds male heterogamety is observed as males produce two different types of gametes.

पर्याय

• Both (A) and (R) are true and (R) is the correct explanation of (A).

• Both (A) and (R) are true, but (R) is not the correct explanation of (A).

• (A) is true, but (R) is false.

• (A) is false, but (R) is true.

Answer 1

(A) is true, but (R) is false.

Explanation:

Sex in humans and many other animals is determined by the XX-XY system. Males are heterogametic because they create two types of sperm, one carrying X and the other carrying Y, due to their XY chromosomes. Females only generate one type of egg (X) since they have XX chromosomes. But in birds, the converse is true; females have heterogametic ZW sex chromosomes, while males have homogametic ZZ sex chromosomes. The explanation is inaccurate because it discusses birds rather than people.