Question

When rocks are exposed to heat, they _______, which can contribute to thermal stress.

Answer 1

Expands

Step-by-step explanation:

Rocks being exposed to heat tends to expand. This expansion creates thermal stress in the area surrounding that rock. When this expansion takes place under the earth's surface, this expansion makes the tectonic plates to move which further becomes the cause of earthquakes. Hence, the answer is 'expands'.