Answer:
The answer is number two extinction happened, this was the time dinosaurs went extinct ebcause lack of sun because oh how much dirt was blown into the earth atmosphere becuase of the asteriod, third option is talking about big bang theroy so that dosnt apply!
Explanation:
The biosphere. This is the layer that contains all life on the planet.
<span> i think it's the gene pool</span><span>
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Where are the answer choices?