Which one of the following elements is not an essential micronutrient for plant growth?

Options

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

Answer

To determine which element is not an essential micronutrient for plant growth, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Essential Nutrients**: Essential nutrients are those that are required by all plants for their growth and development. They are categorized into two groups: macronutrients and micronutrients.

2. **Identify Macronutrients and Micronutrients**:
- **Macronutrients**: These are required in larger quantities and include elements like carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.
- **Micronutrients**: These are required in smaller quantities and include elements like iron, chlorine, manganese, zinc, copper, boron, and molybdenum.

3. **Analyze the Given Options**:
- The options provided are:
- A) Calcium
- B) Magnesium
- C) Zinc
- D) Copper

4. **Classify Each Option**:
- **Calcium**: This is classified as a macronutrient.
- **Magnesium**: This is also a macronutrient.
- **Zinc**: This is a micronutrient.
- **Copper**: This is also a micronutrient.

5. **Determine the Correct Answer**: Since calcium is classified as a macronutrient and not a micronutrient, the correct answer to the question "Which one of the following elements is not an essential micronutrient for plant growth?" is **A) Calcium**.

### Summary:
The element that is not an essential micronutrient for plant growth is **Calcium**.

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