Choose the correct one.

Options

A. C, H, O are called frame work elements
B. `Ca^(2+), Mg^(2+), K^(+)` are protoplasmic elements
C. C, H, O, N are balancing elements
D. All of the above

Answer

To solve the question "Choose the correct one," we need to analyze the options provided and determine which statement is accurate regarding the elements mentioned.

### Step-by-Step Solution:

1. **Understanding the Options:**
- **Option 1:** Carbon, Hydrogen, Oxygen are called framework elements.
- **Option 2:** Calcium, Magnesium, and Potassium are protoplasmic elements.
- **Option 3:** Carbon, Hydrogen, Oxygen, and Nitrogen are balancing elements.
- **Option 4:** All of the above.

2. **Evaluating Option 1:**
- Carbon, Hydrogen, and Oxygen are indeed referred to as framework elements because they form the basic structure (or skeleton) of organic molecules in cells. They are essential for the formation of carbohydrates, lipids, proteins, and nucleic acids.
- **Conclusion:** This option is correct.

3. **Evaluating Option 2:**
- Calcium, Magnesium, and Potassium are important for various cellular functions, but they are not typically classified as protoplasmic elements. Protoplasmic elements usually refer to elements that are part of the protoplasm, like Carbon, Hydrogen, Oxygen, and Nitrogen.
- **Conclusion:** This option is incorrect.

4. **Evaluating Option 3:**
- Carbon, Hydrogen, Oxygen, and Nitrogen are not referred to as balancing elements. Instead, they are the primary elements found in biological molecules and are present in the highest proportions in cells.
- **Conclusion:** This option is incorrect.

5. **Evaluating Option 4:**
- Since Options 2 and 3 are incorrect, Option 4 ("All of the above") cannot be correct.
- **Conclusion:** This option is incorrect.

6. **Final Conclusion:**
- The only correct statement is Option 1: Carbon, Hydrogen, Oxygen are called framework elements.

### Answer:
**The correct answer is Option 1: Carbon, Hydrogen, Oxygen are called framework elements.**

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