Answer:
If the active site is altered, the enzyme can no longer perform its catalytic activity
Explanation:
Changes in temperature or pH alters the structure of the enzyme. Enzymes have catalytic activity that lowers the activation energy required for a reaction to proceed.
Enzyme catalytic activity is facilitated by the active site - a specific region of the enzyme where the reactants bind.
At the active site, the conditions are optimal for the reaction to take place (the active site gets the reactants in the perfect position to make contact and react).
If the structure of the active site is compromised, it won't have catalytic activity anymore and won't be able to catalyze the reaction