This is due to sahara desert and cold water current flowing on it
Answer:
The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust, or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.
Explanation:
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B. Both continental and ocean-floor topography are measured relative to sea level
Explanation:
On a topographic map, both continental and ocean-floor topography are measured relative to sea level.
The sea level is the reference surface for the continental and ocean floor topography.
- A topographic map is a map that shows landform using series of contour lines.
- The lines joins places of equal elevation.
- The elevation is usually referenced to the sea level surface.
- The sea level is taken as the surface with 0 depth or height.
- Continental topography is all places above the sea level.
- Ocean floor is below the sea level surface
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<span>Conduction probably is the main method in the crust, but do not underestimate fluid convection. Every time you find a hot spring, then that is an example of fluid convection. ... Since these two are separate heat transfer from the outer core to the mantle is also mainly by conduction</span>
The answer is none of the above
