Survival time of sperms introduced into the vagina may be
$1-2$ days
$3-4$ days
$5-10$ days
$1$ week
Chorion is composed of
The blastula of prototherians is called
Cu ions released from copper- releasing Intra Uterine Devices $(IUDs)$
Tertiary egg membrane is
Uterine endometrium, epithelial glands and connective tissue are broken in menstrual phase. This is due to