Question

what causes matter to change to a different phase? a change in energy a change in volume

Explanation:

Phase changes in matter occur due to a change in energy. Adding or removing energy can cause a substance to change between solid, liquid, and gas phases. For example, heating ice (solid) gives it energy to melt into water (liquid). A change in volume is a result of a phase - change rather than a cause of it.

Answer:

a change in energy