The shortest gestation period is seen in

The most rapid growth of the human foetus occurs during which month?

In a human foetus,the limbs and digits develop by the end of:

During gastrulation,$.......$ is formed.

The amnion of the mammalian embryo is derived from:

$A$: If both the ovaries are removed after the first trimester of pregnancy,still there would be normal growth of the foetus.
$R$: After the first trimester,the placenta secretes sufficient progesterone.