Enzyme present in sperm acrosome to dissolve egg membrane is
Sperm lysine
Ovolysin
Spermatogenolysin
Spermatocynin
After gastrulation the roof of archenteron is formed by
The corpus luteum secretes ........
The first sign of the growing foetus may be noticed by listening to the heart sound carefully through the stethoscope. Embryo's heart is formed _________.
Animal $\quad$ Gestation period
Ejaculation is the $...A...$ response. Erection is a $...B...$ response. Here, $A$ and $B$ refers to
Antrum is cavity of