Question

grass grows on a lawn. this is a physical change this is a chemical change a sugar cube is ground up. this is a physical change this is a chemical change ice melts. this is a physical change this is a chemical change

Explanation:

1. Grass growing on a lawn involves biochemical processes like photosynthesis, respiration etc. where new substances are formed at the cellular - molecular level. So it is a chemical change.
2. Grinding a sugar cube only changes its physical form (from a cube to powder), without changing its chemical composition (it is still sucrose). So it is a physical change.
3. Melting ice changes its state from solid to liquid, but the chemical substance remains water ($H_2O$). So it is a physical change.

Answer:

1. This is a CHEMICAL change
2. This is a PHYSICAL change
3. This is a PHYSICAL change