How can natural selection affect the songs that birds sing?

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.

An example of a trait that would be considered acquired and inherited is a. a cleft chin b. muscle tone c. scar tissue d. freckled skin

Recommend a strategy for incorporating sustainable human activity into a tropical rain forest biome.