Why the chances of survival of young ones is greater in viviparous ?

Development of an egg without fertilization is called

Which of the following statements are correct regarding female reproductive cycle?

$A$. In non-primate mammals cyclical changes during reproduction are called oestrus cycle.

$B$. 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.

Which of the following option is not correct about sexual reproduction

$(I)$ Gametes fuse to form the zygote

$(II)$ It is an elaborate, complex and fast process as compared to asexual reproduction

$(III)$ Offspring sare not identical to the parents

Identify the events $(A, B, D$ and $E)$ in life of general reproduction