D. They both involve chemical change.
Both photosynthesis and combustion are chemical changes. In photosynthesis, green plants produce their food in the presence of sunlight using carbon dioxide and water.
Combustion refers to something being burnt. It usually applies to burning of fossil fuels.
These processes are both chemical changes because:
- they are not reversible processes
- new products are formed.
- mass is conserved
- they require considerable amount of energy.