Answer: alters the shape of the active site of the enzyme
Explanation: I know you don't need the answer anymore but I thought I'd still explain. So I hope you already know but in case you don't enzymes are typically folded proteins that can react with certain molecules and break them apart through either hydrolysis, the addition of a water molecule to make two separate molecules, or dehydration synthesis, the removal of a water molecule to make two separate molecules. This is made possible when a molecule, or a catalyst, interacts with our enzyme by fitting into the region known as the active site, which is the only place on our enzyme that can actively separate things. It has a very specific shape, and just like many things, when heated up, it can fall apart or deform. In biology, we refer to it as denaturing, which essentially means its shape has changed so much, that our molecules can no longer fit into the enzyme. This makes it impossible or very difficult for the molecule to interact which in turn would make the reaction slow down. When you remove the catalysts or the enzymes, you slow down the reaction because there's nothing helping it speed up.
