The solid mass of cells formed at the end of cleavage of a mammalian egg is:

Major features of embryonic development at various months of pregnancy are given below. Choose the correct option for the correct sequential events.
$(i)$ The first movements of the foetus
$(II)$ The foetus develops limbs and digits
$(III)$ The embryo's heart is formed
$(IV)$ The body is covered with fine hairs

Select the odd one out.

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

Which hormone is responsible for the maintenance of pregnancy?

Which processes occur during the development of an embryo from a zygote?
$I$. Cell division
$II$. Meiosis
$III$. Cell differentiation