Critical Reasoning (CR) | Exposure to a large dose of something that causes bodily damagesuch

Exposure to a large dose of something that causes bodily damage—such as excessive heat, poison, or nuclear radiation—is of course harmful to an organism. But, surprisingly, exposure to small doses of such stressors has been shown to extend life span in various species, including fruit flies, protozoans, worms, and rodents.
Which one of the following, if true, most helps to explain the surprising phenomenon described above?

(A) In most of the species in which exposure to small doses of stressors
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