The gestation period of rabbit is

At what stage the primitive streak in the chick embryo is formed

Rapid secretion of $LH$ in ovulation causes

What is correct for Testis of human ?

shape - Length

Choose the correct combination of the labelling for the following structure.

Assertion : Old age is not an illness. It is a continuation of life with decreasing capacity for adaptation.

Reason : Cessation of mitosis is a normal genetically programmed event.