The third cleavage of frog development is:

$A$: In frog,a gray crescent is formed during fertilization.
$R$: It is because the black pigment granules move away from the point of entry of the sperm in the animal half.

In the adult phase of a frog,which of the following characters becomes degenerate?

In some eggs,future organs can be demarcated even before cleavage begins. This type of development is called

The blastopore is the opening of which structure?

In the development of a frog, the gastrulation process involves: