The correct answer is option 1 - enzymes. Enzymes are bio-catalysts that are used by organisms to break down complex substances into simpler substances. Enzymes are proteins that speed up chemical reactions in living organisms. They act as biological catalysts by lowering the activation energy required for a reaction to occur, allowing the reaction to happen more quickly. Enzymes are highly specific, meaning that each enzyme catalyzes a specific reaction. They are involved in various biochemical processes in the body, such as digestion, metabolism, and synthesis of molecules. Option 2, hormones, are chemical messengers that regulate various processes in the body but do not directly break down substances. Option 3, vitamins, are essential nutrients required in small amounts for various bodily functions but do not act as catalysts.