Answer :
Electrons can be either passed on to the electron transport chain by NADH⁺ at the first complex (NADH⁺-coenzyme Q oxidoreductase) or at the second complex(FADH⁺-coenzyme Q oxidoreductase). I think that's what you're referring to.
Electrons can be either passed on to the electron transport chain by NADH⁺ at the first complex (NADH⁺-coenzyme Q oxidoreductase) or at the second complex(FADH⁺-coenzyme Q oxidoreductase). I think that's what you're referring to.