Primary deficiency in plants is caused by all, except,

Options

A. Nitrogen
B. Potassium
C. Phosphorus
D. Sulphur

Answer

To solve the question regarding which nutrient does not cause primary deficiency in plants, we need to analyze the given options: Nitrogen, Potassium, Phosphorus, and Sulphur.

### Step-by-Step Solution:

1. **Understanding Primary Deficiency**: Primary deficiency in plants occurs when there is an inadequate supply of essential nutrients that are required in larger quantities. These nutrients are typically classified as macronutrients.

2. **Identifying Macronutrients**: The primary macronutrients essential for plant growth include:
- **Nitrogen (N)**: Required in large amounts for the synthesis of proteins and nucleic acids. It is absorbed mainly in the form of nitrates.
- **Phosphorus (P)**: Important for energy transfer (ATP), nucleic acids, and cell membranes. It is also a macronutrient.
- **Potassium (K)**: Involved in various physiological processes, including enzyme activation and osmoregulation. It is also a macronutrient.

3. **Evaluating Sulphur**:
- **Sulphur (S)** is classified as a secondary macronutrient. While it is essential for the synthesis of certain amino acids and proteins, it is not considered a primary macronutrient like Nitrogen, Phosphorus, and Potassium.

4. **Conclusion**: Since Sulphur is not categorized as a primary nutrient, it does not cause primary deficiency in plants. Therefore, the correct answer to the question is **Sulphur**.

### Final Answer:
The nutrient that does not cause primary deficiency in plants is **Sulphur**.

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