Answer:
Reactants or Products?
The answer is reactants.
Reactants Definition- A reactant is the chemical substances present at the start of a chemical reaction.
A products definition is the substance produced in a chemical reaction.
The answer is reactants because they start at the beginning of a chemical reaction, and have to interact with other substances to make a product. product is not able to interact with new substances, nor make new substances. Therefore, in a chemical reaction, if you want the substances to interact, and form new substances, it has to be a reactant.
A way to remember this is think of it as if you are a reactant and you are interacting to form new substances.