Sperms are released from the seminiferous tubules by the process called .....

The amniotic fluid is taken out with the help of surgical needle and separation of the embryo cells present in this fluid is done by

Which one of the following events immediately follows the entry of a spermatozoan into an oocyte

Placenta is formed from

Phallic organs in cockroach are related to

Which cavity arises by the invagination of endoderm and mesoderm