The male sex hormone 'testosterone' is secreted by special Leydig's cells present in

Which of the following gland pairs is $NOT$ present in the human male reproductive system?

Given below is a diagram of the $T.S.$ of a testis. Select the option which gives the correct identification of the function of cells labeled $A, B, C,$ and $D$ from the options given below.
$A$ - cells undergo spermatogenesis to produce spermatozoa.
$B$ - cell responsible for the development of male secondary sexual characters.
$C$ - heads of sperms remain attached to these cells.
$D$ - haploid male gamete.

Seminiferous tubules develop a central lumen after:

The given figure shows the male reproductive system of a human. Select the correct set for the labeled parts $A, B, C$ and $D$.

In humans,the testis functions as