In mammals, in which organ is the $Corpus Luteum$ found?

Following are some events occurring during the fertilization process. Arrange the $CORRECT$ sequence of events and choose the option given below.
$i$. Fertilizin-antifertilizin reaction.
$ii$. Cortical reaction.
$iii$. Acrosome reaction.
$iv$. Karyogamy.
$v$. Capacitation of sperms.

Who demonstrated the acrosome reaction in Saccoglossus?

Sperm of animal species $X$ cannot fertilize ovum of species $Y$ because . . . . . . .

Which lytic enzyme present in the sperm helps in penetrating the corona radiata during fertilization?

$A$ layer of cortical granules is found beneath the