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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.

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?