In general, enzymes are what kinds of molecules?
1) Nucleic acids
3) Lipid molecules
Answer: (4) Proteins
Explanation: Enzymes are bio-active protein molecules found in the cells of both prokaryotes and eukaryotes. Interestingly, enzymes are specific to a particular substrate. They contribute to specialized functions in all living organisms for converting the substrate to a specific product through an enzymatic reaction.
Enzymes are two types, simple and complex enzymes. Simple enzymes are only proteins, while complex enzymes are made up of protein and cofactors.
The main characteristics of enzymes are given in this post: 20 Characteristics of enzymes.