Oestrus cycle is seen in

Fill in the blanks:
$(a)$ Humans reproduce . . . . . . (asexually/sexually)
$(b)$ Humans are . . . . . . (oviparous/viviparous/ovoviviparous)
$(c)$ Fertilization is . . . . . . in humans. (external/internal)
$(d)$ Male and female gametes are . . . . . . (diploid/haploid)
$(e)$ Zygote is . . . . . . (diploid/haploid)
$(f)$ The process of release of the ovum from a mature follicle is called . . . . . .
$(g)$ Ovulation is induced by a hormone called the . . . . . .
$(h)$ The fusion of the male and the female gametes is called . . . . . .
$(i)$ Fertilization takes place in the . . . . . .
$(j)$ The zygote divides to form . . . . . . which is implanted in the uterus.
$(k)$ The structure which provides vascular connection between the fetus and uterus is called . . . . . .

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.

Fraternal twins are produced when

Match the following columns:

Column-$I$	Column-$II$
$(1)$ Secretory phase	$(a)$ $14^{th}$ day
$(2)$ Ovulation	$(b)$ $1-5$ days
$(3)$ Luteal phase	$(c)$ $15-28$ days
$(4)$ Menstrual phase	$(d)$ $6-13$ days
$(5)$ Follicular phase	$(e)$ $15-28$ days

The figure given below shows the sectional view of an ovary. Select the option which gives the correct identification of the marked structure ($A$ to $D$) and its feature.