Here's why:

* Magma: This is molten rock found beneath the Earth's surface.

* Extrusive: This refers to the process of magma erupting onto the Earth's surface, usually through volcanoes.

* Cooling and Hardening: When magma reaches the surface, it cools rapidly due to exposure to the atmosphere and water. This rapid cooling results in the formation of crystals, creating the igneous rock.

Let me know if you have any other questions!