Answer:
How Convection Works. Convection currents form because a heated fluid expands, becoming less dense. The less-dense heated fluid rises away from the heat source. As it rises, it pulls cooler fluid down to replace it. This fluid in turn is heated, rises and pulls down more cool fluid.
Explanation: Hope this helps.
Answer:
Increased oxygen concentration
Explanation:
The evolution of O2-producing cyanobacteria that use water as terminal reductant transformed Earth's atmosphere to one suitable for the evolution of aerobic metabolism and complex life. The innovation of water oxidation freed photosynthesis to invade new environments and visibly changed the face of the Earth.
The process of circular motion in the Earth's mantle that causes the plates of the lithosphere to move is called convection.
The answer is B. convection
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