Each epididymis consists of a single tightly coiled tube whose length is about
$20\,cm$
$20\,feet$
$20\,metres$
None of these
Human placenta is derived from
The extra embryonic membranes of the mammalian embryo are derived from
In Pheretima mouth develops from which of the following
Extra embryonic membrane amnion is not found in amphibians because
Blastodisc or germinal disc refers to the protoplasm of egg, this is restricted to small area in