When a foetus develops limbs and digits?
By the end of $12$ weeks of pregnancy
By the and of second month of pregnancy
By the end of $24$ weeks of pregnancy
During fifth month of pregnancy
$A$ : Failure of testes to descend into the scrotum causes sterility in man.
$R$ : Higher internal body temperature is not suitable for sperm development.
Give scientific reasons : When male excites sexually epididymis wall shrinks / contracts.
Yolk of egg in the vertebrates is formed in
When the cleavage furrow extends from animal pole to vegetal pole and does not bisects the egg equally into two blastomeres the plane of cleavage is
The correct sequence of spermatogenetic stages leading to the formation of sperms in a mature human testis is