Tablets to prevent contraception contain
Progesterone
$FSH$
$LH$
Both $(b)$ and $(c)$
The amnion of mammalian embryo is derived from
Which cavity arises by the invagination of endoderm and mesoderm
In Pheretima mouth develops from which of the following
Which of the following layers in an antral follicle is acellular?
The only human system that is derived from all the three germ layers is