Who is known as the father of modern embryology?

The structure which remains unchanged during the metamorphosis of a frog's tadpole is:

The blastopore develops into the future

During embryonic development,the establishment of polarity such as anterior/posterior,dorsal/ventral,and medial/lateral axes is called:

In the first phase of gastrulation of amphibians,there occurs the separation of:

The beginning of archenteron formation in the development of a frog represents which stage?