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

In human females,the process of parturition is induced by a complex neuroendocrine mechanism. Which of the following triggers the release of oxytocin for parturition?

Which of the following hormones stimulates milk secretion in females?

$A$: 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.

Which hormone is responsible for milk ejection after the delivery of a newborn?

Statement-$I$: Parturition is induced by a complex neuroendocrine mechanism.
Statement-$II$: Oxytocin acts on the uterine muscles and causes stronger uterine contraction.