A chemical process is one in which compositional changes take place. In other words, new compounds are formed by chemical reaction and changes take place at elemental level (elements bond with different elements to form new compounds). Physical processes, on the other hand, do not result in formation of new compounds or new bonds. Physical processes, generally, cause observable changes, without changing the compound. Examples of physical processes include, melting, evaporation, etc.
Photosynthesis is a chemical process, since we make new compounds. In this process, plants use carbon dioxide and water, in the presence of sunlight, and generate glucose molecules, along with oxygen. Here is the chemical equation of photosynthesis:
`6 CO_2 + 6H_2O + (sun light) -> C_6H_12O_6 + 6O_2`
Since, we are generating new compounds, photosynthesis is a chemical process. Interestingly, we are dependent on this process for food and oxygen.
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