Correct option is C
Explanation of Each Statement:
A. "The core body temperature varies least with the changes of environmental temperature."
Correct
Core temperature is tightly regulated by the hypothalamus. It does not fluctuate significantly with changes in external temperature (thanks to homeostatic mechanisms).
B. "During severe muscular exercise the rectal temperature may rise up to 40°C."
Correct
Rectal temperature is a good measure of core body temperature.
During intense exercise, core temperature may rise significantly, even approaching 40°C, especially in athletes or extreme heat.
C. "The oral temperature is relatively higher than the rectal temperature."
Incorrect
Rectal temperature is usually higher than oral temperature by ~0.3 to 0.5°C.
Hence, this statement is wrong.
D. "The core body temperature is highest at 6:00 AM and lowest in the evening in humans who sleep at night and remain awake during daytime."
Incorrect
Circadian rhythm causes lowest core temperature around 4–6 AM, and highest in the late afternoon or early evening (around 4–6 PM).
This statement is incorrect (it reverses the timing).
E. "The temperature of scrotum is regulated at 37°C."
Incorrect
The scrotal temperature is maintained at around 34–35°C, lower than core body temperature, to support spermatogenesis.
So, regulated at 37°C is incorrect.
F. "In women, a rise of basal body temperature occurs immediately after ovulation."
Correct
After ovulation, progesterone secretion increases, causing a slight rise (0.3–0.5°C) in basal body temperature.
This is used in fertility tracking. So, this is correct.
Incorrect Statements:
C – Wrong (oral temp < rectal temp)
D – Wrong (core temp lowest in early morning, not highest)
E – Wrong (scrotal temp is ~34°C, not 37°C)
