A phenomenon of embryonic induction was first described in amphibia by

$A$ : Lack of menstruation may be indicative of pregnancy.
$R$ : Menstruation only occurs if the released ovum is fertilised.

In a mesolecithal egg, one would expect

$A$ : 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

Assertion : Old age is not an illness. It is a continuation of life with decreasing capacity for adaptation.

Reason : Cessation of mitosis is a normal genetically programmed event.