Secretion of progesterone by the corpus luteum is initiated by

Which of the following statements are correct regarding the female reproductive cycle?
$A$. In non-primate mammals,cyclical changes during reproduction are called the oestrus cycle.
$B$. The first menstrual cycle begins at puberty and is called menopause.
$C$. Lack of menstruation may be indicative of pregnancy.
$D$. Cyclic menstruation extends between menarche and menopause.
Choose the most appropriate answer from the options given below.

Secretion of large quantities of estrogen causes:

Describe the location and function of the following: Placenta and Acrosome.

When mammary glands of a male develop similar to that of a female,this condition is known as:

The eggs of an elephant are: