Which cavity arises by the invagination of endoderm and mesoderm?

$A$: Placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and from the embryo.
$R$: Placenta acts as an endocrine tissue.

Identify the correct labeling and its function from the given diagram of a developing fetus.

Which processes occur during the development of an embryo from a zygote?

If you remove all cells that form the endoderm from an egg in the gastrula stage,the new organism will lack which of the following?

Progesterone is secreted by: