Choose the wrong statement.

Options

A. In grasshopper, besides autosomes, males have only one -X-chromosome whereas females have a pair of X-chromosomes.
B. In Drosophila, males have one X-and one Y-chromosome whereas females have a pair of X-chromosomes besides autosomes.
C. In birds, females have one Z-and one W-chromosome, whereas males have a pair of Z- chromosome besides autosomes.
D. In insects with XO type of sex determination, all sperms have X-chromosomes besides autosomes.

Answer

D

Explanation

Grasshopper and cockroach is an example of XO type of sex determination in which the males have only one chromosome besides the autosomes, whereas females have a pair of X-chromosomes.
Among the male Drosophila an X-chromosome is present but its counterpart is distinctly smaller and called the Y-chromosome. Females, however, have a pair of X-chromosomes. Both males and females bear same number of autosomes.
In birds, females have one Z and one W chromosome, whereas male have a pair of Z-chromosomes besides the autosomes.
It was also observed that in a large number of insects the mechanism of sex determination is of the XO type, i.e. all eggs bear an additional X-chromosome besides the other chromosomes (autosomes). On the other hand, some of the sperms bear the X-chromosomes some whereas some do not.