$A$ : The most immediate effect of $FSH$ is the maturation of existing late primary or secondary follicle.
$R$ : $A$ rising level of $FSH$ causes the developing egg within the follicle to complete the first meiotic division to form a secondary oocyte.

$A$ : 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

After a sperm has penetrated an ovum in the process of fertilization, entry of further sperms is prevented by

Sperm lysins contains

Which hormone level reaches peak during luteal phase of menstrual cycle?