Final answer:
It is true that viable sperm production is optimal below the body's core temperature because sperm are immobile at higher temperatures and spermatogenesis is sensitive to temperature changes.infertility can result from the testes not properly descending during fetal development since they need to be kept at a cooler temperature than the rest of the body
Step-by-step explanation:
The statement that viable sperm production is optimal below the body's core temperature is true. Sperm production, or spermatogenesis, occurs within the seminiferous tubules of the testes and is highly sensitive to temperature changes. The anatomical arrangement of the testes being located outside the body in the scrotum is essential for maintaining this cooler environment. The scrotum's temperature is generally about 2 degrees Celsius cooler than the core body temperature, which is conducive for the production of viable sperm. This temperature regulation is achieved through the contraction of smooth muscles within the scrotal sac; when it is too cold, the muscles contract to bring the testes closer to the body's warmth, and they relax to cool down when it is too hot.
In addition, infertility can result from the testes not properly descending during fetal development since they need to be kept at a cooler temperature than the rest of the body. This external positioning is essential, as sperm are immobile at body temperature, requiring the testes to be suspended outside the body for effective motility and fertility.