In the mammalian embryo,the excretory material is stored in:

The vascular system and excretory organs are developed from which germ layer?

In which month of gestation,the first movements of the fetus and the appearance of hair on its head are observed?

Foetal sex can be determined by examining cells from the amniotic fluid by looking for

Match the items $A, B, C, D$ of table $'A'$ with the items in table $'B'$. Then,the correct pairing sequence of $A, B, C, D$ will be:
Table $'A'$ | Table $'B'$
$A.$ Cleavage | $1.$ Formation of $3$ germ layers
$B.$ Gastrulation | $2.$ Formation of embryo spinal cord
$C.$ Neurulation | $3.$ Results in formation of skeleton and muscles from mesoderm
$D.$ Organogenesis | $4.$ Pattern depends on the amount and distribution of yolk

Explain the difference between the following terms:
$(1)$ Menstrual flow - Menstrual cycle
$(2)$ Embryo - Foetus