Which of the following is a macronutrient?

Options

A. Mo
B. Ca
C. Zn
D. Mn

Explanation

To determine which of the following is a macronutrient, we first need to understand what macronutrients are. Macronutrients are essential nutrients that organisms require in large amounts for growth and development. They include carbohydrates, proteins, and fats, as well as certain minerals and water.

### Step-by-Step Solution:

1. **Define Macronutrients**:
- Macronutrients are substances required by living organisms in large quantities. They are crucial for energy production, growth, and overall health.

2. **Identify Common Macronutrients**:
- The primary macronutrients include:
- Carbohydrates (e.g., sugars, starches)
- Proteins (made up of amino acids)
- Fats (lipids)
- Water (though not always classified with the others)
- Certain minerals (like nitrogen, phosphorus, potassium) are also considered macronutrients in the context of plant nutrition.

3. **Evaluate the Options**:
- If provided with a list of options, look for substances that fall under the categories mentioned above. For example, if the options include nitrogen, potassium, calcium, and iron, then nitrogen, potassium, and calcium would be considered macronutrients.

4. **Select the Correct Answer**:
- Based on the evaluation, choose the option that is classified as a macronutrient.

### Example:
If the options were:
- A) Iron
- B) Nitrogen
- C) Copper
- D) Zinc

The correct answer would be **B) Nitrogen**, as it is a macronutrient essential for plant growth.