Hormone, which is responsible for contraction of uterus is

$A$ : Synthesis of milk is stimulated by rise in the level of oxytocin.
$R$ : Oxytocin is released from the adenohypophysis under influence of hypothalamus.

Give scientific reasons : When birth time is near, two chemical signals associated and produces real parturition pain / labour pain.

Foetal ejection reflex in human female is induced by

$A$ -Colostrum contains several antibodies.

$R$ -Due to colostrum immunity is decrease in child.