Which gland helps in the lubrication of the penis during coitus?

Given below are two statements:
Statement-$I$: The scrotum helps in maintaining the low temperature of the testes.
Statement-$II$: Low temperature,compared to the normal internal body temperature,is necessary for spermatogenesis.
In the light of the above statements,choose the most appropriate answer from the options given below.

Which of the following statements is incorrect about Leydig cells?

During early and middle fetal life,the testes are located in the:

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 functional unit of the human testis?