What type of igneous rock cools and solidifies on or very near the Earth’s surface?

What type of igneous rock cools and solidifies on or very near the Earth’s surface?

• A. Intrusive rock
• B. Metamorphic rock
• C. Extrusive rock
• D. Basaltic rock

Answer: (C)

The correct choice is extrusive rock. This type of igneous rock forms when magma erupts onto the Earth's surface as lava, where it cools and solidifies relatively quickly. The rapid cooling process results in the formation of fine-grained crystals, giving extrusive rocks distinct characteristics. Common examples include basalt and pumice. Intrusive rocks, in contrast, cool and solidify beneath the Earth's surface, allowing for slower cooling and the formation of larger crystals. Metamorphic rocks are not igneous at all; they form from existing rocks that have been altered through heat, pressure, or chemical processes. While basaltic rock refers specifically to a type of extrusive rock with a composition rich in iron and magnesium, it does not encompass the broader category of rocks formed at or near the surface like extrusive rock does.

The correct choice is extrusive rock. This type of igneous rock forms when magma erupts onto the Earth's surface as lava, where it cools and solidifies relatively quickly. The rapid cooling process results in the formation of fine-grained crystals, giving extrusive rocks distinct characteristics. Common examples include basalt and pumice.

Intrusive rocks, in contrast, cool and solidify beneath the Earth's surface, allowing for slower cooling and the formation of larger crystals. Metamorphic rocks are not igneous at all; they form from existing rocks that have been altered through heat, pressure, or chemical processes. While basaltic rock refers specifically to a type of extrusive rock with a composition rich in iron and magnesium, it does not encompass the broader category of rocks formed at or near the surface like extrusive rock does.