The extra-embryonic membranes of the mammalian embryo are derived from

$A$: The first sign of a growing foetus may be noticed by listening to the heart sound through the stethoscope.
$R$: By the end of the second month of pregnancy,the foetus develops limbs and digits.

The figure below shows a human fetus within the uterus. Identify $P$ and $Q$.
$\quad\quad P \quad\quad\quad Q$

The minimum number of barriers present between foetal and maternal blood is present in which type of placenta?

Blood flowing in the umbilical cord of a mammalian embryo is:

The first movement of the fetus and the appearance of hair on the head are usually observed during which month of pregnancy?