A. concentrated is the substance on its own, dilute is the substance mixed with (diluted) water.
B. an acid increases the concentration of H+ ions. A base is a substance that releases hydroxide (OH-) ions (in aqueous solution, donates electrons and accepts protons)
Pepsin is an enzyme that breaks down proteins to polypeptides so if you add pepsin to aprotein it will break it down into smaller molecules of polypeptides
