Magma tends to rise toward the earhs surface principally because?

Question

Magma tends to rise toward the earhs surface principally because?

Answer 1

Either the density of the magma is less than that of the surrounding rock or it is less dense because it is hotter, or both. Much magma motion is due to convection.

Answer 2

Because of the build-up pressure in the magma chamber which lies under every volcano.

Answer 3

Magma is generated when rock deep underground melts due to the high temperatures and pressures inside the earth. Because magma is lighter than the surrounding rock, it tends to rise. As it moves upward, the magma encounters colder rock and begins to cool. If the temperature of the magma drops low enough, the magma will crystallize underground to form rock; rock that forms in this way is called intrusive, or plutonic igneous rock, as the magma has formed by intruding the surrounding rocks. If the crust through which the magma passes is sufficiently shallow, warm, or fractured, and if the magma is sufficiently hot and fluid, the magma will erupt at the surface of the earth, possibly forming volcanoes. Magma that erupts is called lava.