One of the following is almost not found in living organism-

Options

A. Si
B. Mg
C. Ca
D. S

Answer

To solve the question of which element is almost not found in living organisms, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements Given**: The options provided are Silicon, Magnesium, Calcium, and Sulfur.

2. **Analyze Each Element**:
- **Silicon**: It is present in very small amounts in living organisms, primarily found in nails and hair.
- **Magnesium**: This element is essential for life and is found in significant amounts in the body, primarily as Mg²⁺ ions, playing a crucial role in ATP synthesis.
- **Calcium**: This is another essential element found in the body, particularly in bones and teeth, and is involved in various physiological processes.
- **Sulfur**: This element is important for the formation of certain amino acids, vitamins, and chlorophyll in plants.

3. **Determine the Element with Minimal Presence**: Among the four elements, Silicon is the one that is found in the least amount in living organisms.

4. **Conclusion**: Based on the analysis, the element that is almost not found in living organisms is **Silicon**.

### Final Answer:
The correct answer is **Silicon** (Option 1).

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