Eunuchoidism is due to the failure of production of

The eggs in which fate of every part of the egg becomes fixed are called

Cleavage was first observed by

The respiratory function of embryo is performed by

$A$ : Most birds possess only the left ovary and left oviduct for conveying the ovum released from the ovary.
$R$ : The avian ovary does not form a corpus luteum from the ruptured ovarian follicle which undergoes rapid shrinkage