A spiral metabolic sequence can best be described as one in which
A. The product of the first reaction is the starting material for the next reaction, and so on.
B. A series of reactions regenerates the initial reactant.
C. The various reactions have virtually no connection to one another.
D. The same set of enzymes progressively builds up or breaks down a molecule.
E. The same set of enzymes catalyses the same reaction in both the forward and reverse directions.
D. Which statement is true