Here's why:
* Intrusive means that the magma (molten rock) intruded into pre-existing rock layers within the Earth's crust.
* Extrusive igneous rocks, on the other hand, are formed when lava (magma that has erupted onto the surface) cools and solidifies.
Some examples of intrusive igneous rocks include:
* Granite: A coarse-grained rock often found in mountain ranges.
* Gabbro: A dark-colored, coarse-grained rock found in ocean basins.
* Diorite: A medium-grained rock with a mixed composition.
* Peridotite: A very dense, coarse-grained rock found deep within the Earth's mantle.
