Placenta is formed from
Maternal part only
Embryonic part only
Maternal and foetal portions both
None of the above
Zona pellucida of mammalian egg serves which of the following purpose
Which one of the following is the most widely accepted method of contraception in India, at present?
How many sperms are formed by four primary spermatocytes?
Identify the correct option ($A$), ($B$), ($C$), ($D$) with respect to spermatogenesis.
A change in the amount of yolk and its distribution in the egg will affect