What is the significance of the epididymis in male fertility?

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.

Given below is a diagrammatic sketch of a portion of the human male reproductive system. Select the correct set of the names of the parts labelled $A, B, C, D$.

What is the composition of the seminal plasma?

The Leydig cells found in the human body are the source of ...

Choose the correct sequence of sperm transport in humans starting from the seminiferous tubules: