Which one of the following elements is not required by plants for their healthy normal growth?

Options

A. Calcium
B. Magnesium
C. Lead
D. Iron

Answer

### Step-by-Step Solution:

1. **Identify the Question**: The question asks which element is not required by plants for their healthy and normal growth.

2. **Review the Options**: The options provided are:
- A) Calcium
- B) Magnesium
- C) Lead
- D) Iron

3. **Understand Essential Elements**: Plants require certain elements for their growth, which are classified into:
- **Macronutrients**: Elements needed in larger quantities (e.g., nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur).
- **Micronutrients**: Elements needed in smaller quantities (e.g., iron, manganese, zinc, copper, molybdenum, and boron).

4. **Evaluate Each Option**:
- **Calcium**: An essential macronutrient important for cell wall structure and signaling.
- **Magnesium**: A crucial macronutrient that is a central component of chlorophyll and is involved in many enzyme functions.
- **Lead**: Not an essential nutrient for plants and can be toxic.
- **Iron**: An essential micronutrient important for chlorophyll synthesis and various metabolic processes.

5. **Conclusion**: Based on the evaluation, the element that is not required by plants for healthy growth is **Lead** (Option C).

### Final Answer:
**C) Lead**

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