Which one of the following elements is almost non - essential for plants ?

Options

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

Answer

To determine which element is almost non-essential for plants from the given options (Zinc, Sodium, Calcium, or Molybdenum), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Categories of Nutrients**:
- Nutrients for plants are classified into two main categories: macronutrients and micronutrients.
- Macronutrients are required in large quantities, while micronutrients are needed in trace amounts.

2. **Identify the Macronutrients**:
- From the options provided, Calcium is recognized as a macronutrient. It is essential for various functions in plants, including being a part of the cell wall and membrane, and acting as an enzyme activator.

3. **Identify the Micronutrients**:
- Zinc and Molybdenum are both classified as micronutrients.
- Zinc is important for protein synthesis and is a component of chlorophyll, while Molybdenum is involved in the nitrogen cycle as a component of certain enzymes.

4. **Evaluate Sodium**:
- Sodium is not classified as an essential nutrient for plants. While it can play a role in some metabolic processes and can be utilized for chlorophyll synthesis, plants can grow and develop without it.

5. **Conclusion**:
- Based on the classifications and functions of the nutrients discussed, the element that is almost non-essential for plants is Sodium.

### Final Answer:
Sodium is almost non-essential for plants.

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