Question

Rocks that have been changed from previously existing rocks (but that were not completely melted) by the action of heat, pressure, and associated chemical activity are?

1) intrusive rocks.
2) igneous rocks.
3) metamorphic rocks.
4) sedimentary rocks.
5) punk rocks.

Answer 1

Rocks altered by heat, pressure, and chemical processes without melting are called metamorphic rocks, and include forms like schist and marble. The correct answer is option 3.

Step-by-step explanation:

Rocks that have been changed from previously existing rocks by the action of heat, pressure, and associated chemical activity, but that were not completely melted, are known as metamorphic rocks. These rocks, such as schist, slate, and marble, occur when existing rocks, be they igneous or sedimentary, are subjected to conditions that cause physical or chemical alterations.

This process is part of what geologists refer to as the rock cycle, which involves the transformation of rocks through geological time driven by tectonic activities. Metamorphism can result in distinctive patterns and orientations of minerals within the rock, such as foliation, which occurs without the rock melting.