Answer:
e) Substrate
Step-by-step explanation:
An enzyme substrate binds to the enzymes active site which speeds up a reaction, forming an enzyme-substrate complex. Enzyme catalyzes the reaction and form a product from a specific substrate resulting in an enzyme-product complex. They are highly specific and each can only catalyze and bind to its own specific substrate or reactant.
Eg; Starch is a substrate (reactant) which is converted to maltose!(Product) by amylase enzyme.