The mammary gland is a modification of which of the following glands in Eutherians?

Which hormone inhibits the menstrual cycle in females during the period of lactation?

In an adult human female,oxytocin is responsible for:

$A$: Oxytocin acts on the uterine muscles and causes stronger uterine contractions,which in turn stimulates further secretion of oxytocin.
$R$: Oxytocin is released from the maternal pituitary.

Lactiferous duct is present in

Which of the following immunoglobulins (antibodies) is present in the highest concentration in human milk?