Which of the following drugs inhibits metamorphosis in frogs?

In a frog,how many ova and spermatozoa are produced from $50$ secondary oocytes and $50$ secondary spermatocytes,respectively?

During the development of an amphibian embryo,what is the significance of the point of entry of the sperm into the egg at fertilization?

If the size of a fertilized egg of a frog is compared with the size of its blastula and gastrula stages,which of the following observations will be correct?

In which of the following is $Bidder's$ canal present?

Fertilization is external in: