- Heat is a kind of energy
- Exposure to extreme heat and pressure changes igneous rock into metamorphic rock
- So, exposure to heat energy can change igneous rock into metamorphic rock

- Exposure to heat energy can change igneous rock into metamorphic rock
- Change is a kind of process
- Hence, heat energy is in the process of changing igneous rock to metamorphic rock

So, heat energy is in the process of changing igneous rock to metamorphic rock
When igneous rock is changed into metamorphic rock, which form of energy is this process?
- Heat is a kind of energy 
- Change is a kind of process 
- Exposure to extreme heat and pressure changes igneous rock into metamorphic rock