The following pair of elements are relatively abundant in living organisms than in earth.s crust

Options

A. Oxygen Nitrogen
B. Magnesium , Carbon
C. Carbon , Sodium
D. Carbon , Hydrogen

Answer

To solve the question regarding which pair of elements are relatively more abundant in living organisms than in the Earth's crust, we can follow these steps:

### Step 1: Identify the Elements in the Options
We have the following options to analyze:
1. Oxygen and Nitrogen
2. Magnesium and Carbon
3. Carbon and Sodium
4. Carbon and Hydrogen

### Step 2: Compare the Abundance of Each Element in Living Organisms and Earth's Crust
We need to look at the abundance of these elements in both living organisms and the Earth's crust.

- **Oxygen**:
- Earth's Crust: ~47%
- Living Organisms: ~65%

- **Nitrogen**:
- Earth's Crust: ~0.002%
- Living Organisms: ~3%

- **Magnesium**:
- Earth's Crust: ~2.2%
- Living Organisms: ~0.01%

- **Carbon**:
- Earth's Crust: ~0.9%
- Living Organisms: ~9.5%

- **Sodium**:
- Earth's Crust: ~2.5%
- Living Organisms: ~0.03%

- **Hydrogen**:
- Earth's Crust: ~0.022%
- Living Organisms: ~63%

### Step 3: Analyze Each Option
1. **Oxygen and Nitrogen**:
- Oxygen is more abundant in living organisms than in the Earth's crust, but nitrogen is less abundant in the crust. This option does not satisfy the condition of both being more abundant in living organisms.

2. **Magnesium and Carbon**:
- Magnesium is more abundant in the Earth's crust than in living organisms, so this option is incorrect.

3. **Carbon and Sodium**:
- Carbon is more abundant in living organisms, but sodium is less abundant in living organisms than in the Earth's crust. This option does not satisfy the condition.

4. **Carbon and Hydrogen**:
- Both carbon and hydrogen are more abundant in living organisms than in the Earth's crust. This option satisfies the condition.

### Step 4: Conclusion
The correct answer is **Carbon and Hydrogen** as they are relatively more abundant in living organisms than in the Earth's crust.

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