What is magma? a. the molten mixture of rock-forming substances, gases, and water from the mantle.. c. hardened lava on the surface of the earth. b. liquid rock that reaches the surface. d. all of the above select the best answer from the choices provided a b c d

A. The molten mixture of rock-forming substances, gases, and water from the mantle

Magma is a mass of molten rock that is found in the deepest layers of the Earth at high temperature and pressure, and that can flow out through a volcano.

The composition of this mass is a mixture of liquids, volatile and solids that when they reach the surface in an eruption becomes lava, which when cooled crystallizes and gives rise to the formation of igneous rocks.