In larger terrestrial animals, the testes are in the scrotum rather than in the abdomen There is lack of room in the abdomen A. This provides for a shorter sperm path B. This provides a more direct blood supply C. It provides greater protection to the testes D. It keeps the temperature lower for sperm development

D. It keeps the temperature lower for sperm development

Explanation:

Semineferous epithelium ,of the seminiferous tubules, of the testis  is the site of  sperm production (Spermatogenesis) , and highly sensitive to elevated and fluctuating body temperature of  man. Elevated temperature affect the survival of spermatids , the spermatozaon,  and therefore affects spermatogenesis.

To avoid this the testis is located outside the body  in the scrotal sack.This positioning aids  shielding away  of the elevated body temperature; thereby survival of spermatozoan.

The attachment in the scrotal sack is done by the cremasteric muscles of  the scrotum. This muscle positions the testis in the best angle  to reduce temperature conduct from the body.

It also help by contracting and relaxing,  to adjusts the temperature of the testis depending on the environmental temperature.During cold showers,it constricts pulling it close to the abdomen, and after, relaxes returning it to normal position.

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there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: