Final answer:
The dartos muscle contraction elevates the scrotal sac to regulate the temperature of the testes, which is essential for optimal spermatogenesis.
Step-by-step explanation:
Contraction of the dartos muscle results in C. elevates the scrotal sac. The dartos muscle is located in the subcutaneous layer of the scrotum and works in conjunction with the cremaster muscle to regulate the temperature of the testes. In response to cold temperatures, the dartos and cremaster muscles contract, pulling the testes closer to the body, and reducing the surface area of the scrotum to conserve heat.
During warmer conditions, these muscles relax, allowing the testes to lower away from the body, increasing the scrotal surface area to facilitate heat loss. This thermoregulatory response is essential to maintain the optimal temperature for spermatogenesis, as excessive heat can harm sperm development.