Answer: The earth's atmosphere support life on earth by protecting us from the UV rays and slows down asteroids before they hit the earth. And protects us from much more stuff.
Explanation:
Because natural selection can only increase or decrease frequency of alleles that already exist in the population
Luster
density
streak
hardness
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<span>Some bacteria in the soil fix nitrogen into useful forms for plants to use them. This conversion of nitrogen helps plants grow. Without the bacteria in the soil a lot of the plants would not be able to grow.</span>