The main function of erythrocytes is to .....for which they contain a special protein , called …..

Explanation

**Step-by-Step Solution:**

1. **Identify Erythrocytes**: Erythrocytes are commonly known as red blood cells (RBCs). They are the most abundant type of cells in the blood.

2. **Understand the Structure**: Erythrocytes have a unique biconcave shape which increases their surface area for gas exchange. They lack a nucleus and other organelles, which allows more space for hemoglobin.

3. **Function of Erythrocytes**: The primary function of erythrocytes is the transport of gases. They are responsible for carrying oxygen from the lungs to the tissues and transporting carbon dioxide from the tissues back to the lungs.

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