Which of the Following Statements Is True Regarding Enzyme Pathways

Multiple Choice

Which of the following statements is true regarding enzyme pathways?

A) the most effective way to control a pathway is to regulate every enzyme in the pathway
B) an enzyme pathway always proceeds in only one direction, never in reverse
C) a regulatory enzyme is regulated only by molecules within the given pathway
D) metabolic pathways are necessary since enzymes usually catalyze only one specific reaction
E) none of the above are true