During the development of embryo which of the following occur first
Differentiation of tissue
Differentiation of cells
Differentiation of organs
Differentiation of organ system
The extra structure that provides nutrition to the embryo is
Which one of the following is temporary endocrine gland
Identify $X$ from figure :
In Human beings, at the end of $12$ weeks (first trimester) of pregnancy, the following is observed
The role of placenta is