The human body does not produce:-

Options

A. Enzyme
B. Vitamins
C. Proteins
D. Nucleic acid

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which substance the human body does not produce. We have four options to consider: enzymes, vitamins, proteins, and nucleic acids.

2. **Analyzing Each Option**:
- **Enzymes**: The human body produces enzymes, which are biological catalysts that speed up chemical reactions in the body.
- **Vitamins**: The human body does not produce vitamins. Vitamins are essential nutrients that must be obtained from the diet.
- **Proteins**: The body synthesizes proteins from amino acids through the process of translation and transcription.
- **Nucleic Acids**: The human body can produce nucleic acids (DNA and RNA) as they are essential for genetic information and cellular function.

3. **Identifying the Correct Answer**: Based on the analysis, the only substance that the human body does not produce is vitamins.

4. **Conclusion**: Therefore, the correct answer to the question is **Vitamins**.

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