When infected by a virus, a host cell produce many thousands of identical copies of the original virus. so the answer is B
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Answer;
-NAD+
Explanation;
-When glucose breaks down into ATP, a large amount of the energy is stored as electron on special molecules (the electron carriers). When an empty electron carrier accepts a pair of electrons, it is reduced; when it gives those electrons up later on, it is oxidized.
-NAD+ and FAD; also the two most common electron carriers in the body. NAD+ can accept a pair of electrons (and a hydrogen ion) to become NADH.

The digestion of protein begins at mouth and it continues at stomach and small intestine.
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The answer is E, control sperm production.