Final answer:
Extrusive igneous rocks are formed when molten material is deposited on the surface and cools quickly, resulting in fine-grained textures.
Step-by-step explanation:
The igneous rocks that are deposited on the surface and then cooled are known as extrusive igneous rocks. Extrusive igneous rocks form when molten material, called magma, flows out onto the surface or into cracks near the Earth's surface and cools quickly. As a result of this rapid cooling, extrusive igneous rocks have fine-grained textures.