Answer:
The damage to ozone layer is done by halogens such as Chlorine and Bromine.
Answer:
Early cyanobacteria in stromatolites are thought to be responsible for increasing the amount of oxygen in the primeval Earth's atmosphere through their continuing photosynthesis. They were the first known organisms to photosynthesize and produce free oxygen.
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I think 1 is C and 2 is A
They help pump blood at a greater distance than Atria can.
<span>Scientists consistently link two catastrophic events with the five major mass extinctions recorded throughout Earth's history. These two events are
A) global ice ages and the impact of asteroids.
Global ice ages led to the extinction of many populations over time, whereas when asteroids hit Earth, dinosaurs disappeared, among other species.
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