Smoking increases______ content in blood and reduces the concentration of haembound oxygen. Fill blank suitably

Options

A. Carbon dioxide
B. Carbaminohaemoglobin
C. Carbon monoxide
D. Carboxylic acid

Explanation

To fill in the blank in the statement "Smoking increases______ content in blood and reduces the concentration of heme-bound oxygen," we need to analyze the effects of smoking on the blood.

### Step-by-Step Solution:

1. **Understanding the Effects of Smoking**: Smoking primarily involves inhaling tobacco smoke, which contains various harmful substances. One of the most significant components of tobacco smoke is carbon monoxide (CO).

2. **Identifying the Correct Term**: Among the options provided:
- **Carbon Dioxide**: While smoking does increase CO2 levels, it is not the primary harmful gas associated with smoking.
- **Carbaminol Hemoglobin**: This term refers to a form of hemoglobin that is bound to carbon dioxide, but it is not directly relevant to the primary effects of smoking.
- **Carbon Monoxide**: This is a toxic gas that binds to hemoglobin more effectively than oxygen, leading to reduced oxygen transport in the blood.
- **Carboxylic Acid**: This is not a relevant term in the context of smoking and its effects on blood.

3. **Conclusion**: Given that smoking increases the level of carbon monoxide in the blood, which in turn reduces the concentration of heme-bound oxygen, the correct answer to fill in the blank is **"carbon monoxide."**

### Final Answer:
Smoking increases **carbon monoxide** content in blood and reduces the concentration of heme-bound oxygen.

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