Which of the following is a micronutrient?

Options

A. Ca
B. Mg
C. K
D. Ni

Answer

To determine which of the following options is a micronutrient, we need to classify each nutrient based on whether it is a macronutrient or a micronutrient.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Macronutrients**: These are nutrients required by plants in larger quantities. Examples include Calcium, Magnesium, Nitrogen, Phosphorus, and Sulfur.
- **Micronutrients**: These are nutrients required in smaller amounts. Examples include Zinc, Boron, Nickel, Chlorine, Molybdenum, and Copper.

2. **Analyze the Given Options**:
- **Calcium**: This is classified as a macronutrient because it is needed in larger quantities for plant growth.
- **Magnesium**: While it is essential for plants, it is also considered a macronutrient because it is required in relatively larger amounts compared to micronutrients.
- **Potassium**: This is another macronutrient, as it is required in significant amounts for various physiological functions in plants.
- **Nickel**: This is classified as a micronutrient because it is required in very small quantities.

3. **Conclusion**:
- Among the options provided, Nickel is the only nutrient that qualifies as a micronutrient.

### Final Answer:
The correct answer is **Nickel**.

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