The immobile element in plants is

Options

A. Calcium
B. nitrogen
C. phosphorus
D. magnesium

Answer

To solve the question regarding the immobile elements in plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Essential Elements**:
- Essential elements are necessary for the growth and development of plants. They are categorized into macronutrients (needed in larger quantities) and micronutrients (needed in smaller quantities).

2. **Differentiate Between Mobile and Immobile Elements**:
- Mobile elements are those that can move within the plant from one part to another. In contrast, immobile elements remain in one location and are not transported throughout the plant.

3. **Identify the Elements in the Options**:
- The question provides options, and we need to evaluate each to determine if they are mobile or immobile.

4. **Evaluate Calcium**:
- Calcium is a macronutrient that is absorbed from the soil in the form of calcium ions. It plays a crucial role in the synthesis of the plant cell wall and is involved in enzyme activation. Importantly, calcium is considered an immobile element because once absorbed, it does not move to other parts of the plant.

5. **Evaluate Other Elements**:
- Nitrogen is a macronutrient that is mobile within the plant.
- Phosphorus is also a mobile element.
- Magnesium is another macronutrient that is mobile.

6. **Conclusion**:
- Among the options given, the only immobile element is Calcium. Therefore, the correct answer to the question is Calcium.

### Final Answer:
The immobile element in plants is **Calcium**.

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