In the chemical process of photosynthesis, sunlight is primarily considered a(n)
a)
catalyst.
b)
enzyme.
c)
product.
d)
reactant.

The answer would be:

D. Reactant

In photosynthesis, light energy is considered as a reactant. The reactants of photosynthesis include, water, carbon dioxide and light energy. The sun provides the light energy needed, which is absorbed by the chloroplasts.

This is the chemical equation of photosynthesis:

12H20 + 6CO2 + light energy → C6H12O6 + 6H2O + 6O2