Most Enzymes Catalyze a Chemical Reaction in Both Directions

Multiple Choice

Most enzymes catalyze a chemical reaction in both directions.Which is the best explanation of this statement?

A) Chemical reaction in both directions means the direction and rate of the reaction is being governed by gravity; for example, food in the lower digestive tract is moved by peristalsis, whereas food in the upper part of the digestive tract is moved by segmentation.
B) Chemical reaction in both directions means that enzymes are both intracellular and extracellular, depending on whether they act within cells or outside them in the surrounding medium.
C) Chemical reaction in both directions means the direction and rate of the reaction is being governed by the rate law or law of mass action; for example, slowing of digestion when absorption is interfered with and the products of digestion accumulate.
D) Both B and C are accurate explanations.