Answer:
The correct answer would be "NADH delivers its electrons to complex I and FADH₂ deliver its electrons to complex II" in cellular respiration.
There are mainly four complexes associated with electron transport chain of cellular respiration.
Complex I or NADH: ubiquinone oxidoreductase is the complex at which NADH is oxidized to form NAD⁺. The free electrons are transported with the help of ubiquinone.
Complex II or succinate dehydrogenase is the complex associated with oxidation of FADH₂ to FAD⁺. It also transports the free electrons with the help of the ubiquinone pool.
Complex III or cytochrome bc1 complex transport free electrons from ubiquinone to the cytochrome C which is a water-soluble electron carrier.
Complex IV or cytochrome c oxidase transport the free electrons to oxygen to form water.
Coal, oil, and, natural gas
The inferior vena cava brings deoxygenated blood back into the heart from the lower body. For comparison, the part that directs deoxygenated blood from the upper body is the superior vena cava.