100ml. Pure blood carries `:-`

Options

A. `1.34 ml. O_(2)`
B. 20 ml. `O_(2)`
C. 15 ml. `O_(2)`
D. 4 ml. `O_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding Blood Composition**: Blood is composed of plasma and cells, primarily red blood cells (RBCs) which contain hemoglobin. Hemoglobin is responsible for carrying oxygen.

2. **Amount of Hemoglobin in Blood**: In 100 ml of pure blood, there is approximately 15 grams of hemoglobin.

3. **Oxygen Carrying Capacity of Hemoglobin**: Each gram of hemoglobin can carry about 1.34 ml of oxygen. Therefore, to find out how much oxygen can be carried by 15 grams of hemoglobin, we multiply:
\[ \text{Oxygen carried} = \text{grams of hemoglobin} \times \text{oxygen per gram} \]
\[ \text{Oxygen carried} = 15 \, \text{g} \times 1.34 \, \text{ml/g} = 20.1 \, \text{ml} \]

4. **Conclusion**: Thus, 100 ml of pure blood can carry approximately 20 ml of oxygen.

5. **Oxygen Utilization by Tissues**: While 20 ml of oxygen is carried, only about 4 ml of oxygen is typically delivered to the tissues for their metabolic needs.

6. **Final Answer**: The correct answer to the question "100 ml of pure blood carries" is **20 ml of oxygen**.

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