Answer:
D. Glycolysis
Explanation:
In glycolysis, energy is required to break a molecule of glucose into two pyruvate molecules. These two pyruvate molecules are used during pyruvate oxidation; which is stage II of cellular respiration.
During glycolysis, two molecules of ATP are used and four molecules of ATP are produced. So there is a net gain of two ATP molecules. Hydrolysis of a glucose molecule produces high energy electrons which are used to reduce two NAD+ molecules to NADH.
These two molecules are used in the citric acid cycle to produce more ATP molecules.
