Answer :

Primary classification trait used to explain how scientists divide rocks into the three classification groups is the basis of how they were formed.

What is the three classification groups of rocks?

There are three types of stones: igneous, sedimentary and metamorphic. Igneous rocks forms when molten rock (magma or lava) cools and solidifies. Sedimentary rocks form when particles settle from water or air, or by precipitation of minerals from water. They accumulate in layers. Metamorphic rocks occur when existing rocks are changed by heat, pressure, or reactive fluids, such as hot water, that contain many minerals. Most rocks are made of minerals containing silicon and oxygen, the most abundant elements in the earth's crust.

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