The abundant elements in living beings is

Options

A. Oxygen
B. Nitrogen
C. Carbonic acid and bicarbonate
D. Hydrogen.

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for the most abundant element in living beings.

2. **Consider the Options**: The options provided are:
- A) Oxygen
- B) Nitrogen
- C) Carbonic Acid
- D) Bicarbonate
- E) Hydrogen

3. **Analyze Each Option**:
- **Oxygen**: It is known to be a major component of water, which makes up about 70% of the human body. Additionally, oxygen is vital for respiration.
- **Nitrogen**: While nitrogen is important for amino acids and nucleic acids, it is not the most abundant.
- **Carbonic Acid**: This is a compound formed in solution when carbon dioxide is dissolved in water; it is not an element.
- **Bicarbonate**: Similar to carbonic acid, it is a compound and not an element.
- **Hydrogen**: Although hydrogen is abundant, it is not as abundant as oxygen in terms of body weight.

4. **Determine the Most Abundant Element**: Based on the analysis, oxygen is the most abundant element in living beings, comprising about 65% of the total body weight in humans.

5. **Conclusion**: The correct answer is **A) Oxygen**.

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