Why the colour of the blood is red?

Options

A. Plasma
B. Haemoglobin
C. Red blood corpuscles
D. White blood corpuscles

Explanation

**Step-by-Step Solution:**

1. **Understanding Blood Composition**: Blood is composed of various components, including red blood cells (RBCs), white blood cells (WBCs), plasma, and platelets. Each component has a specific function.

2. **Identifying the Pigment**: The red color of blood primarily comes from a specific pigment known as hemoglobin. Hemoglobin is a protein found in red blood cells.

3. **Role of Iron**: Hemoglobin contains iron, which is crucial for its function. The iron in hemoglobin is in the ferrous (Fe²⁺) state, which is responsible for the red coloration.

4. **Function of Hemoglobin**: Hemoglobin's main role is to transport oxygen from the lungs to the rest of the body and to carry carbon dioxide back to the lungs for exhalation. The binding of oxygen to hemoglobin also contributes to its red color.

5. **Conclusion**: Therefore, the reason blood appears red is due to the presence of hemoglobin in red blood cells, which contains iron and gives blood its characteristic color.

**Final Answer**: The color of blood is red due to the pigment hemoglobin present in red blood cells, which contains iron.

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