Question

what is the primary way that metamorphic rocks form?

a. lava erupts from earth and cools.

b. water, wind, and gravity move particles from one place to another.

c. rock fragments break apart and collect as sediment.

d. existing rocks join together under high heat and pressure.

Explanation:

Metamorphic rocks are formed when existing rocks are subjected to high - heat and high - pressure conditions, which cause physical and chemical changes in the rock. Option A describes the formation of igneous rocks. Option B describes erosion and transportation processes. Option C describes sediment formation.

Answer:

D. Existing rocks join together under high heat and pressure.