Here's why:

* Definition: Enzymes are proteins (though some are RNA molecules) that act as biological catalysts. They speed up biochemical reactions within living organisms without being consumed in the process.

* Specificity: Enzymes are highly specific. Each enzyme catalyzes a particular reaction or a small set of related reactions. This specificity is crucial for the precise regulation of biochemical processes.

* Example: One well-known example is lactase, an enzyme that breaks down lactose (milk sugar) into simpler sugars that can be absorbed by the body. People who lack lactase experience lactose intolerance.

Let me know if you'd like to explore other examples of biological catalysts or learn more about specific enzymes!