Oxygen is required for cellular respiration, it is an aerobic process. When no oxygen is present, the anaerobic process(a process that doesn't require oxygen) called fermentation begins creating ATP in smaller amounts. In cellular respiration, Oxygen is used to move electrons through the electron transport chain, and remove excess hydrogen and electrons in the form of water,
<span>C. It binds to the coding region and adds nucleotides to the growing end of the DNA.
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