Which of the following is not a macronutrient?

Options

A. Ca
B. P
C. Mn
D. N

Answer

To determine which of the following is not a macronutrient, we need to analyze the options provided: calcium, phosphorus, manganese, and nitrogen.

### Step-by-Step Solution:

1. **Understand Macronutrients**: Macronutrients are nutrients that are required by organisms in large amounts. They are essential for various bodily functions and metabolic activities. Common macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

2. **List the Options**: The options given are:
- Calcium
- Phosphorus
- Manganese
- Nitrogen

3. **Identify Macronutrients from the Options**:
- **Calcium**: This is a macronutrient as it is required in large amounts for various physiological functions, including bone health.
- **Phosphorus**: This is also a macronutrient, essential for energy transfer and storage in the form of ATP.
- **Nitrogen**: This is a macronutrient, crucial for the synthesis of amino acids and nucleic acids.
- **Manganese**: This is not a macronutrient; it is classified as a micronutrient, which is needed in smaller amounts.

4. **Conclusion**: Since manganese is the only element in the options that is not classified as a macronutrient, the correct answer to the question is manganese.

### Final Answer:
**Manganese is not a macronutrient.**

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