Which of the following hormones is not secreted by the human placenta?

What is the correct sequence of development?

The gestation period in human beings is about:

Which of the following glands undergoes differentiation during pregnancy?

Allantois develops from the embryonic

$A$ : The morula passes through the phase of compaction,producing two major types of cells: the peripheral cells and the inner cell mass.
$R$ : The descendants of the inner cell mass become the trophoblast cells.