1. Ice melts and becomes water. This is physical change as only state of water from solid to liquid has changed in this process.
2. Bud blossoms to a flower, this is a chemical change as once a bud blooms into a flower, it cannot revert back to its bud form. Also, internal chemical changes takes place.
3. Cold water becomes warm on keeping in open, this is a physical change as water remains the same, only its temperature changes.
4. Rotting of banana is a chemical change as its composition and texture get changed.