The primordial germ cells make their appearance from wall of

Both corpus luteum and macula lutea are

The eggs in which fate of every part of the egg becomes fixed are called

The amnion and chorion consist of which type of composition

$I. $ Sperm cells immediately when they are released from the body and are placed in a petri plate remain alive for much longer duration.

$II.$ Semen contains chemicals that causes females smooth muscles to contract

Mammalian embryo is directly surrounded by