Answer: Construction of a transcontinental railroad. Mark me brainiest
What do you mean and how is this a question?
There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water.
They should study about how volcanoes erupt or explodes
Explanation:
the igneous composition contains mostly olivine crystals with minor amounts of pyroxene is <em><u>Mafic</u></em>
