For carbohydrates, it would be chemically digested (digestions that involves enzymes) in 2 locations, the oral cavity, and the duodenum (small intestine).
In the oral cavity, salivary amylase is secreted by salivary glands. It can turn starch (large carbs) into Maltose (a smaller sugar molecule).
And in the duodenum, intestinal amylase and carbohydrase is produced, and specifically carbohydrase can break Maltose into glucose, which is the final form of carbs our body requires.
They're then absorbed in the ileum, a lower part of small intestine.
Photosynthesis is 6 CO2 + 6H2O---> C6H12O6 + 6 O2. So unless I understand the question wrong, none is needed to do, but glucose and oxygen are products after the photosynthesis
