The capsule enclosing the testis of a mammal is called:

Sertoli cells are found in

Which of the following glands is not present in pairs in the male reproductive system?

$A$: Occasionally,mammary glands are functional in males,and the condition is called gynaecomastia.
$R$: Decreased testosterone in later life may also lead to gynaecomastia. It is usually due to the perturbation of the estrogen-to-androgen ratio.

Draw a labeled diagram of the male reproductive system.

The organs which produce gametes are called $...A...$ and those which neither produce gametes nor hormones are called $...B...$. Here $A$ and $B$ represent: