Here's why:

* Active Site: The active site is a specific three-dimensional region on the enzyme where the substrate(s) bind. It's like a lock and key mechanism, where the substrate's shape perfectly complements the active site's shape.

* Products Site: There is no separate "products site". Once the substrate(s) bind to the active site, the enzyme facilitates the chemical reaction, converting the substrates into products. These products then detach from the enzyme, leaving the active site free for another round of catalysis.

Let me know if you have any other questions!