How does an organism obtain C6H12O6 and O2 to
undergo respiration?

oxygen is given off during photosynthesis as a waste product

Explanation:

this is something that only plants and some algae and bacteria can do. they take sunlight and combined C02 and H20. they create glucose (C6H1206) and oxygen gas (02).

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