Answer:
Oxygen
Explanation:
Kreb's cycle, also known as the Tricarboxylic acid cycle (TCA), is the second process of aerobic cellular respiration, after glycolysis. In the kreb's cycle, acetyl-CoA from pyruvic acid is oxidized to CO2 with the formation of 2 ATP molecules.
Krebs cycle occurs in the matrix of the mitochondria where chemical energy in form of ATP, NADH and FADH2 are produced. Krebs cycle is termed an AEROBIC process because it requires OXYGEN in order to occur.
