Which of the following are critical elements necessary for plant growth ?

Options

A. C,H,O
B. Ca,Mg,S
C. N,P,K
D. Mn,Fe ,Cu

Answer

To determine the critical elements necessary for plant growth, we need to analyze the options provided and identify which elements are essential for various physiological processes in plants.

### Step-by-Step Solution:

1. **Identify Major Elements**: Begin by identifying the major elements that are known to be critical for plant growth. The primary macronutrients include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S).

2. **Evaluate Each Element**:
- **Carbon (C)**: While essential for forming the backbone of organic molecules (proteins, starch, cellulose), it is not classified as a critical element for growth in the same way as macronutrients.
- **Hydrogen (H)**: Important for photosynthesis and ATP formation, but again, not a primary growth element.
- **Oxygen (O)**: Necessary for cellular respiration, but not directly tied to growth.
- **Calcium (Ca)**: Important for cell wall structure, but not a direct growth enhancer.
- **Magnesium (Mg)**: A key component of chlorophyll, essential for photosynthesis and thus indirectly supports growth.
- **Sulfur (S)**: Important for protein synthesis and enzyme function, contributing to growth.

3. **Focus on Nitrogen, Phosphorus, and Potassium**:
- **Nitrogen (N)**: A major component of chlorophyll and amino acids, crucial for plant growth.
- **Phosphorus (P)**: Vital for DNA and RNA synthesis, energy transfer (ATP), and root development.
- **Potassium (K)**: Plays a significant role in regulating photosynthesis and overall plant metabolism.

4. **Micronutrients**: Elements like manganese, iron (ferrous), and copper are important but are considered micronutrients rather than macronutrients. They play roles in various biochemical processes but are not classified as critical elements necessary for growth in the same way as N, P, and K.

5. **Conclusion**: The critical elements necessary for plant growth are nitrogen, phosphorus, and potassium.

### Final Answer:
The critical elements necessary for plant growth are **Nitrogen (N), Phosphorus (P), and Potassium (K)**.

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