The cell membrane a. controls which substances enter and exit the cell. b. alters and packages proteins and lipids. c. is the site of most cellular chemical reactions. d. converts glucose to other energy molecules.

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.

Why is the theory of evolution important? it disproves all other theories about how life began. it provides a topic for debate. it is a unifying concept in biology. it explains how life began. i know for sure, it is not "it is a unifying concept in biology."

Which of the following happened during the precambrian era? the first prokaryotic cells the first eukaryotic cells development of photosynthesis all of the above