By which time of pregnancy are the limbs and digits developed in the fetus?

Which structure connects the fetus to the placenta in mammals during pregnancy?

Which structure is responsible for the production of the hormone progesterone?

Which of the following organs is differentiated first during human embryonic development?

Breast development during pregnancy is induced by

Find the correct statements :
$A.$ In human pregnancy,the major organ systems are formed at the end of $12$ weeks.
$B.$ In human pregnancy the major organ systems are formed at the end of $8$ weeks.
$C.$ In human pregnancy heart is formed after one month of gestation.
$D.$ In human pregnancy,limbs and digits develop by the end of second month.
$E.$ In human pregnancy the appearance of hair is usually observed in the fifth month.
Choose the correct answer from the options given below.