Identify the parts $a, b, c, d$ in the given diagram of the male reproductive system.

Describe the location and function of Sertoli cells and Leydig cells.

Label $A, B, C, D$ in the following diagram of the male reproductive system.

The cells of $Leydig$ produce and secrete .......... .

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.

The epididymis leads to $...A...$ that ascends to the abdomen and loops over the $...B....$ Here $A$ and $B$ refer to: