Answer:
reactants
Step-by-step explanation:
The ingredients or materials present at the start of a chemical reaction are called the reactants.
Reactants are species that combines at the start of a reaction to give a product.
For example:
A + B → C
A and B are the reactants
C is the product of the reaction
Therefore, every specie on the left hand side of the reaction are the reactants on the those on the right hand side are the products.