The exchange of materials between blood and interstitial fluid is by

Options

A. arteries
B. veins
C. capillaries
D. arterioles

Answer

**Step-by-Step Solution:**

1. **Understanding Interstitial Fluid**: Interstitial fluid is the fluid that exists in the spaces between cells in tissues. It serves as a medium through which nutrients, gases, and waste products can be exchanged between blood and cells.

2. **Identifying Blood Vessels**: The options provided in the question are arteries, veins, capillaries, and arterioles.
- **Arteries**: These are large blood vessels that carry blood away from the heart.
- **Veins**: These are blood vessels that carry blood back to the heart.
- **Arterioles**: These are smaller branches of arteries that lead to capillaries.
- **Capillaries**: These are the smallest blood vessels where the exchange of materials occurs.

3. **Role of Capillaries**: Capillaries are the key sites for the exchange of materials between blood and interstitial fluid. Their thin walls allow for the diffusion of nutrients, gases, and waste products.

4. **Conclusion**: The exchange of materials between blood and interstitial fluid occurs primarily in the capillaries.

**Final Answer**: The exchange of materials between blood and interstitial fluid is by **capillaries**.

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