The Leydig's cells secrete:

In which of the following are the testes always located within the abdominal cavity?

Leydig cells are found in

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.

What are the seminiferous tubules in the human testis?

Which organ of the human male reproductive system is not paired?