Repressor theory of activation of fertilization was given by

The abdominal passage which connects the abdominal cavity with the scrotal sac in mammals is known as

In eggs which have very thick and resistant membrane e.g., fishes and insects sperm penetrate through a special canal called

Assertion : Senescence is the time when age associated defects are manifested.

Reason : Certain genes may be undergoing sequential switching on and off during one's life.

Cleavage in bird's egg is