Igneous rock is defined as:

Igneous rock is defined as:

• A. A category of rock formed from a molten state
• B. A rock formed from deposited sediments
• C. A rock altered by heat and pressure
• D. A rock formed by precipitation

Answer: (A)

Igneous rocks come from molten material that cools and solidifies. This molten material can be magma that crystallizes underground or lava that erupts onto the surface and then hardens. The cooling rate explains texture: slow cooling forms coarse crystals like granite, fast cooling forms fine crystals like basalt, and very rapid cooling can produce glassy rocks like obsidian. This distinguishes igneous rocks from others. Sedimentary rocks form from accumulated sediments or from minerals precipitating from water, not from melting. Metamorphic rocks form when existing rocks are altered by heat and pressure without melting. The idea of formation by precipitation points to chemical sedimentary rocks, not igneous ones.

Igneous rocks come from molten material that cools and solidifies. This molten material can be magma that crystallizes underground or lava that erupts onto the surface and then hardens. The cooling rate explains texture: slow cooling forms coarse crystals like granite, fast cooling forms fine crystals like basalt, and very rapid cooling can produce glassy rocks like obsidian.

This distinguishes igneous rocks from others. Sedimentary rocks form from accumulated sediments or from minerals precipitating from water, not from melting. Metamorphic rocks form when existing rocks are altered by heat and pressure without melting. The idea of formation by precipitation points to chemical sedimentary rocks, not igneous ones.