Question

1. which describes one thing that happens during thermoregulation when a sensor recognizes that a persons temperature is 39 degrees c?

sweat glands are \shut off.\
muscles under the skin make body hair stand on end.
blood vessels under the skin expand.
the muscles in the body expand and contract quickly, producing friction.

Explanation:

A human's normal core body temperature is around 37°C; 39°C indicates a fever (elevated temperature). Thermoregulatory responses to high body temperature aim to release heat. Sweat glands activate to produce sweat (evaporative cooling), blood vessels under the skin expand to release heat, and muscle shivering (which generates heat) does not occur. The incorrect options describe responses to cold temperatures: sweat glands shutting off, body hair standing on end, and muscle contractions generating heat.

Answer:

Blood vessels under the skin expand.