PLEASE ANSWER!!! 9
When portions of the Earth's mantle partially melt, the melted material (magma) separates from the leftover solid materials. Magma
is richer in silicate minerals and is therefore less dense than the rock from which it melted. Because of its lower density, magma
rises upward toward the Earth's surface. Eventually, the magma may cool at or near the surface to form oceanic crust, which is less
dense than the underlying mantle.
Continental crust forms in a similar way. However, at least part of the magma that forms continental crust is melted from existing
crust instead of the mantle. This magma, and the new continental crust that it ultimately forms, are less dense than oceanic crust.
This explains why continental crust sits higher on the Earth's surface than oceanic crust and causes the Earth to have land above
sea level.
Based on the information above, which of following is true about the Earth's history?
OA.
The first continents formed after the Earth had formed oceanic crust.
OB. Earth's earliest life forms evolved on continents, not in the oceans.
OC.
Earth's first continents had a greater density than the mantle beneath them.
OD
Oceanic crust did not form on Earth until after the first continents had formed.
Undo
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