What does natural selection cause

the mechanism that darwin proposed for evolution is natural selection . because resources are limited in natural organisms with heritable traits that favour survival and reproduction will tend to more offspring than their peers ,causing the traits to increase in frequency over generation .

Explanation:

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he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.