Question

which of the following describes a negative feedback loop?
when the heart rate is too high, the body sends hormones that continually increase the heart rate higher.
when a pregnant woman is in labor, the body sends hormones that increase the intensity of contractions, which then increases the secretion of the same hormones.
when blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows.
when a person is jogging, the body sends hormones that continually decrease the rate of oxygen supply to the legs.

Explanation:

A negative - feedback loop works to maintain a stable state by counteracting changes. When blood sugar is low, the body raises it until it reaches a normal level and then slows hormone secretion, thus returning to a stable state. The other options describe positive - feedback loops (amplifying changes) or incorrect physiological responses.

Answer:

When blood sugar is too low, the body sends hormones that raise blood sugar until it reaches a typical level and hormone secretion slows.