Enzymes are basically _________A. FatB. ProteinC. Nucleic acidD. All of the above

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are primarily made up of proteins. Therefore, the correct answer is:

B. Protein

Explanation: Enzymes are proteins composed of long chains of amino acids. These chains fold into specific three-dimensional shapes, which enable them to catalyze specific biochemical reactions. Some enzymes, known as ribozymes, are made of RNA, but the vast majority of enzymes are proteins.

A. Fat is incorrect because enzymes are not made of fats.
C. Nucleic acid is incorrect because although RNA can have catalytic activity, the majority of enzymes are proteins.
D. All of the above is incorrect because only proteins (and some RNA molecules) serve as enzymes.