The mammalian primitive streak gives rise to

Given below are two statements with respect to gastrulation.
$Statement-I$: Root of amniotic cavity is lined by amniogenic cells, which divides to form chorion.
$Statement-II$: Chorion is an embryonic membrane that participates in development of the embryo.
Choose the most appropriate answer from the options given below.

In the simplest type of placenta,the foetal blood is separated from the maternal blood by six barriers. How many barriers are lost in the human placenta?

The hormone used to prevent abortion is .....

What is the correct sequence of events in the formation of an offspring from a zygote?

Which is not the function of placenta?