Question

multiple choice question
an enzyme inhibitor
o breaks down certain substrates effectively preventing a reaction from proceeding
o binds to the substrate and prevents it from binding the enzyme
o binds to an enzyme and decreases its activity

Explanation:

An enzyme inhibitor is a molecule that interacts with an enzyme to reduce its activity. It doesn't break down substrates (that's the job of enzymes), and while some inhibitors act by binding to the substrate - enzyme complex or the substrate to prevent enzyme - substrate binding, the most general definition is that it binds to an enzyme and decreases its activity.

Answer:

binds to an enzyme and decreases its activity