Answer:
Should be 1 to A, 2 to B, and 3 to C.
Step-by-step explanation:
The active site will be where the reaction takes place, and thus where the substrate will attach to in order for the reaction to begin.
Denaturing a proteins is breaking apart the bonds that hold it together. Denaturation usually occurs when the protein overheats, which is also why high fevers are dangerous. It's our body's natural way of killing viruses due to their similar nature to proteins, but maintaining a high fever for too long often addles the body's senses and ability to understand when to allow itself to cool down.
A catabolic reaction is by name and nature a reaction, so it only makes sense that it be matched to C. Catabolic reactions do build up on each other though. A really good, well-known example is cellular respiration, which is a chain of reaction processes that produce the ATP the human body (and quite frankly, any living body) runs on.