What is the cause of pseudopregnancy?

Match the following columns:

Column-$I$	Column-$II$
$(1)$ Testis	$(a)$ Provides nutrition to sperms
$(2)$ Ovary	$(b)$ Primary male sex organ
$(3)$ Theca interna	$(c)$ Synthesis of testosterone
$(4)$ Sertoli cells	$(d)$ Synthesis of estrogen
$(5)$ Leydig cells	$(e)$ Primary female sex organ

Which of the following groups represents a pair of similar structures or functions?

Which one of the following statements about sex hormones is correct?

Which of the following female structures is homologous to the male structure?

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.