Question

The rate of cleavage in a zygote depends upon

• A. Amount of yolk
• B. Amount of cytoplasm
• C. Size of nucleus
• D. All of the above

Answer 1

The correct option is A Amount of yolk

Cleavage involves the division of embryo at the different developmental stage. The yolk gets deposited on the vegetal pole. It provides nourishment to the growing embryo. Yolk inhibits the mitotic division, therefore, the deutoplasm divides slowly in comparison to the cytoplasm of the animal pole. A number of stored yolk increases, the amount of active cytoplasm, gradually decreases, and the position of the nucleus is variously affected and inhibits mitosis.

So, the correct answer is option A.