Under which conditions do
metamorphic rocks form during regional metamorphism?

Under regional metamorphism, metamorphic rocks are formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.

Explanation:

Metamorphism is the phenomenon in the formation of metamorphic rocks whereby rocks are changed by heat and pressure. Now, during this process called metamorphism, rocks are bound to change either physically and chemically into a new rock. Now, there are two types of metamorphism namely;

Contact metamorphism and regional metamorphism.

We are concerned with regional metamorphism and it is defined as metamorphic rocks formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.

first one is the correct answer