Answer:
May involve a change in phase but does not involve a change in the molecular structure
Explanation:
A physical change is change in phase.
For example a change from liquid to solid or solid to gas etc.
If there is a change at molecular structure it means the process if chemical.
For example breaking of hydrogen molecule to monoatomic hydrogen.
If there is a change involving conversion of one substance to other or generation of new substances then it must be a chemical change.
For example combination of hydrogen with oxygen to form water molecule.
