What is the best description for a Mutagen? A. Inherited factors that cause a mutation. B. Any mutation to DNA. C. Environmental factors that cause a mutation. D. Something that already has a mutation.

option B is correct

The best description for a Mutagen is  Any mutation to DNA because “Mutagen is a physical, chemical or biological agent that causes mutation by altering the genetic material which possibly results in the disease condition.

Explanation:

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thymine. in rna, thymine is replace by uracil

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.