Development of structure and shape of an organism is

After gastrulation the roof of archenteron is formed by

The yolk plug of gastrula represents in the later stage its

Which of the following enzyme helps sperm to penetrate zona pellucida?

$A$ : Failure of testes to descend into the scrotum causes sterility in man.
$R$ : Higher internal body temperature is not suitable for sperm development.

Egg of rabbit and man are