In the electron transport system, hydrogen atoms removed from NADH ultimately end up as part of

Water H2O

Explanation:

In cellular respiration process NAD+ is a most versatile electron acceptor and functions in several of the redox steps during break down of glucose.

Each NADH molecules formed during respiration represents stored energy that can be tapped to make ATP when the electrons complete their ''fall''down an energy gradient from NADH to oxygen.

Electrons removed from glucose are shuttle by NADH to the ''top'', higher-energy end of the electron transport chain. At the ''bottom'' lower energy end, O2 captures these electrons along with H+ forming water.

Therefore Hydrogen removed from NADH in the ETC is captured by O2 to form water

2H + 1/2O2 > H20

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.

i believe the answer is a.