Final answer:
One molecule of FADH2 through the ETC equals approximately two ATP molecules.
Step-by-step explanation:
The student asked how many ATP molecules are produced from one molecule of FADH2 via the electron transport chain (ETC). In the ETC, each FADH2 molecule yields approximately two ATP molecules. This is because FADH2 enters the process at Complex II, unlike NADH, which starts at Complex I and results in the production of about three ATP molecules. Hence, FADH2 contributes less to the ATP yield due to its lower entry point in the chain.