Which of the following statements accurately describes enzymes? a. enzymes slow chemical reactions. b. many different types of substrates with different shapes can bind to a single enzyme. c. temperature and ph can affect how enzymes work. d. enzymes increase the activation energy of reactions.

Match each organ or function with its body system. produces urine large intestine ureters mouth filters blood absorbs nutrients from food

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 concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important