Assertion (A): In human males, the testes are extra-abdominal and lie in scrotal sacs.
Reason (R): The scrotum acts as a thermoregulator and keeps the testicular temperature low (2-2.5°C lower than the normal internal body temperature), which is necessary for spermatogenesis.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both Assertion (A) and Reason (R) are correct and R is the correct explanation of A.
Assertion (A): In human males, the testes are extra-abdominal and lie in scrotal sacs. — True. A is about where the testes are placed. In human males the testes lie outside the abdominal cavity, inside a pouch of skin called the scrotum.
Reason (R): The scrotum acts as a thermoregulator and keeps the testicular temperature low (2-2.5°C lower than the normal internal body temperature), which is necessary for spermatogenesis. — True. R is about what the scrotum does. It keeps the testes 2–2.5 °C cooler than the normal internal body temperature. Sperm formation (spermatogenesis) needs this lower temperature.
Why R explains A? Sperms cannot be formed at the full temperature inside the abdomen. If the testes stayed inside the body, spermatogenesis would fail. By hanging the testes outside the abdomen in the scrotum, the body keeps them cooler than its core. So R gives the reason for the position in A, and R is the correct explanation of A.
NCERT Extract:
The Male Reproductive System – “The male reproductive system is located in the pelvis region (Figure 2.1a). It includes a pair of testes alongwith accessory ducts, glands and the external genitalia. The testes are situated outside the abdominal cavity within a pouch called scrotum. The scrotum helps in maintaining the low temperature of the testes (2–2.5o C lower than the normal internal body temperature) necessary for spermatogenesis.”