Answer:
B. Free-radical theory
Explanation:
The free radical theory statutes that <em>ageing is the result of the accumulation of the damage to cells and tissues caused by reactive oxygen species</em> as a result of aerobic metabolism.
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Idekicoukdnteventellyouthat
Stars are made of very hot gas. This gas is mostly hydrogen and helium, which are the two lightest elements. Stars shine by burning hydrogen into helium in their cores, and later in their lives create heavier elements.