Which contains more carbon dioxide : inhaled air or exhaled air ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Respiration**: Respiration is the process by which organisms take in oxygen and release carbon dioxide. It consists of two main phases: inhalation (inspiration) and exhalation (expiration).

2. **Inhaled Air Composition**: When we inhale, we take in air that primarily contains oxygen (approximately 21% oxygen) and a very small amount of carbon dioxide (about 0.04%).

3. **Exhaled Air Composition**: During exhalation, the body releases air that has a different composition. After the oxygen is used by the body for metabolic processes, carbon dioxide is produced as a waste product.

4. **Carbon Dioxide in Exhaled Air**: The exhaled air contains a significantly higher concentration of carbon dioxide, approximately 4-5% compared to the inhaled air. This is because carbon dioxide is a byproduct of the oxidation of food in the body.

5. **Conclusion**: Therefore, exhaled air contains more carbon dioxide than inhaled air.

**Final Answer**: Exhaled air contains more carbon dioxide than inhaled air.

---