In the context of Darwin's theory of evolution, changes mentioned in the statements can be explained by natural selection, where advantageous traits improve an organism's chance of survival and reproduction.
Natural selection is a key concept in Darwin's theory of evolution. In the context of the statements provided, the changes mentioned, like the hardening of shells in almejas to avoid predators, can be explained by natural selection. Organisms that develop advantageous traits like a harder shell or faster speed have a higher chance of survival and passing on their genes to the next generation, improving the population over time.
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