Differentiate the three main rock types in terms of origin and typical textures.

Differentiate the three main rock types in terms of origin and typical textures.

• A. Igneous rocks form from weathering; Sedimentary rocks form from cooling magma; Metamorphic rocks form from lava.
• B. Igneous rocks form from cooling magma or lava (extrusive or intrusive) with textures ranging from fine to coarse; Sedimentary rocks form from weathering, erosion, deposition, and lithification with clastic, chemical, or organic textures; Metamorphic rocks form from heat/pressure altering existing rocks, with foliated or nonfoliated textures.
• C. Sedimentary rocks form from melting; Igneous rocks form from deposition; Metamorphic rocks from weathering.
• D. Metamorphic rocks form from glassy lava flows.

Answer: (B)

Rock types are categorized by how they form and the textures they typically show. Igneous rocks originate from the cooling and solidification of molten material, whether underground as intrusive rocks with larger crystals or at the surface as extrusive rocks with finer crystals or glass. Sedimentary rocks form from weathered and eroded material that is transported, deposited, and lithified, giving textures that are clastic (fragments), chemical (precipitated minerals), or organic (from remains). Metamorphic rocks arise when existing rocks are altered by heat and pressure, which re-crystallizes minerals and creates textures that are foliated (layered/banded) or nonfoliated (non-layered). This set of descriptions matches the correct understanding of the three rock types. The other choices mix up formation processes—for example, suggesting igneous rocks come from weathering, or metamorphism from lava—or claim metamorphic rocks form from glassy lava flows, which isn’t how metamorphism proceeds.

Rock types are categorized by how they form and the textures they typically show. Igneous rocks originate from the cooling and solidification of molten material, whether underground as intrusive rocks with larger crystals or at the surface as extrusive rocks with finer crystals or glass. Sedimentary rocks form from weathered and eroded material that is transported, deposited, and lithified, giving textures that are clastic (fragments), chemical (precipitated minerals), or organic (from remains). Metamorphic rocks arise when existing rocks are altered by heat and pressure, which re-crystallizes minerals and creates textures that are foliated (layered/banded) or nonfoliated (non-layered).

This set of descriptions matches the correct understanding of the three rock types. The other choices mix up formation processes—for example, suggesting igneous rocks come from weathering, or metamorphism from lava—or claim metamorphic rocks form from glassy lava flows, which isn’t how metamorphism proceeds.