The eggs of a frog are....

In the embryonic development of chordates,the animal pole forms which of the following in the adult?

In a frog,what does the blastopore develop into?

$A$: 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.

The development of the eye in vertebrate embryology is studied under which of the following processes?

The concept that the organiser is essential for embryonic development was given by,or for the 'Theory of organiser',the Nobel Prize was given to: