The number of essential amino acids in adult human is

Options

A. Nine
B. Five
C. Eight
D. Eleven

Answer

**Step-by-Step Text Solution:**

1. **Understanding Essential Amino Acids**: Essential amino acids are those that cannot be synthesized by the body and must be obtained through diet.

2. **Total Amino Acids**: There are a total of 20 different amino acids that the body uses to build proteins.

3. **Identifying Essential Amino Acids**: Out of these 20 amino acids, there are 9 that are classified as essential for adults.

4. **Listing Essential Amino Acids**: The 9 essential amino acids in adults are:
- Leucine
- Isoleucine
- Tryptophan
- Phenylalanine
- Lysine
- Methionine
- Valine
- Threonine
- Histidine

5. **Conclusion**: Therefore, the number of essential amino acids in adult humans is 9.

6. **Final Answer**: The correct answer to the question is 9.

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