Why Aging Isn’t Inevitable

Humans age gradually, but some animals do all their aging in a rush at the end of life, while others don’t age at all, and a few can even age backward. The variety of aging patterns in nature should be a caution sign to anyone inclined to generalize—particularly the generalization that aging is inevitable. Bacteria reproduce symmetrically, just dividing in two. What could “aging” mean for bacteria since, after reproduction, there is no distinction between parent and child?

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