What are the final electron acceptor in electron transport chain?

In aerobic respiration, the final electron acceptor in the electron transport chain  is oxygen.  It accepts two electrons and a molecule of water is formed as a by product.

In anaerobic respiration, the final electron acceptor in the electron transport chain is pyruvate.  Anaerobic respiration  commonly occurs in the muscle tissue of animals as  a result of intense activity or exertion. Pyruvate is used as makeshift electron acceptor in place of oxygen and is reduced or converted to lactic acid.

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answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;