How many cleavages are completed in $16$ celled stage of egg.
$3$
$4$
$8$
$12$
Pasteels $(1945)$ described gastrulation takes place in aves by
Which centriole of spermatozoa is required for first cleavage?
The Graafian follicle ruptures to release _________ from the ovary by the process called ovulation.
Cryptorchidism is the condition in man when
How does zona pellucida of ovum help in preventing polyspermy ?