Which of the following is not essential amino acid

Options

A. Valine
B. Lysine
C. Histidine
D. Glycine

Answer

To determine which of the following is not an essential amino acid, we first need to understand the difference between essential and non-essential amino acids.

### Step-by-Step Solution:

1. **Define Essential Amino Acids**: Essential amino acids are those that cannot be synthesized by the human body and must be obtained from the diet. There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

2. **Define Non-Essential Amino Acids**: Non-essential amino acids are those that can be synthesized by the body. Examples include alanine, aspartic acid, glutamic acid, and glycine.

3. **Identify the Options**: The question would typically provide a list of amino acids. We need to analyze each option to determine if it is essential or non-essential.

4. **Evaluate Each Option**:
- If the option is one of the nine essential amino acids, it is essential.
- If the option is one of the amino acids that can be synthesized by the body, it is non-essential.

5. **Select the Correct Answer**: Based on the analysis, the amino acid that is not essential (i.e., can be synthesized by the body) will be the correct answer.

### Conclusion:
Without the specific options provided in the question, we cannot definitively state which amino acid is non-essential. However, if glycine is one of the options, it is a non-essential amino acid, as it can be synthesized by the body.