Natural Selection is the process in which “Nature” aka all things living, push evolution forward by culling undesirable traits. Note: this doesn’t necessarily mean the very best traits, they are the one’s that allow a creature to reproduce, thus passing along that trait.
A good example is that caterpillar gif from the frontpage yesterday. It’s a caterpillar that evolved to look like a snake, which would deter predators, and help the caterpillar grow up to reproduce. This didn’t happen overnight, rather, it’s more that “caterpillars bearing resemblance to a common predator snake had a better chance of survival” This act over thousands or millions of years continues improving onto the concept until it becomes what it is today.
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