order of occurrence of element in human body is

Options

A. O,C,N,H
B. O,C,H,N
C. Na,Ca,C,O
D. K,Ca,C,Mg

Answer

To determine the order of occurrence of elements in the human body based on their abundance, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements and Their Percentages**:
- Oxygen (O) - 65%
- Carbon (C) - 18.5%
- Nitrogen (N) - 3.3%
- Hydrogen (H) - 1.5%
- Calcium (Ca) - 1.5%
- Sodium (Na) - 0.4%
- Magnesium (Mg) - 0.75%
- Potassium (K) - negligible amount

2. **Rank the Elements by Abundance**:
- Start with the element that has the highest percentage and work downwards.
- The order based on the percentages is:
1. Oxygen (65%)
2. Carbon (18.5%)
3. Nitrogen (3.3%)
4. Hydrogen (1.5%)
5. Calcium (1.5%)
6. Magnesium (0.75%)
7. Sodium (0.4%)
8. Potassium (negligible)

3. **Focus on the Most Abundant Elements**:
- The four most abundant elements that make up approximately 96% of the human body are:
- Oxygen
- Carbon
- Nitrogen
- Hydrogen

4. **Final Order of Occurrence**:
- Therefore, the correct order of occurrence of the four most abundant elements in the human body is:
- Oxygen > Carbon > Nitrogen > Hydrogen

### Conclusion:
The correct order of occurrence of elements in the human body is:
**Oxygen, Carbon, Nitrogen, Hydrogen.**