List the three reactants of photosynthesis represented by the letter a in the diagram.

The 3 reactants of photosynthesis are sunlight/energy, carbon dioxide, and water.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products