When more than one sperm establish contact and penetrate into the egg, then it is called
Monospermy
Polyspermy
$(a)$ and $(b)$ both
None of these
True coelom develops as a split in
The fluid filled in the blastocoel cavity of blastula is
$A$ : The first sign of growing foetus may be noticed by listening to the heart sound through the stethoscope.
$R$ : By the end of second month of pregnancy, the foetus develops limbs and digits.
Placenta is present in
The correct sequence of spermatogenetic stages leading to the formation of sperms in a mature human testis is