Identify the hormones that are secreted in large amount prior to ovulation :

$A.$ $LH$

$B.$ $FSH$

$C.$ $Estrogen$

$D.$ $Progesterone$

A phenomenon of embryonic induction was first described in amphibia by

The yolk plug of gastrula represents in the later stage its

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

Blood flowing in umbilical cord is