What is meant by double circulation ?

Explanation

**Step-by-Step Solution:**

1. **Definition of Double Circulation**: Double circulation refers to the process in which blood passes through the heart twice during one complete cycle of circulation. This means that the blood goes through two distinct pathways: one to the lungs and another to the rest of the body.

2. **Components of Double Circulation**:
- **Pulmonary Circulation**: This is the first part of double circulation. In this pathway, deoxygenated blood is pumped from the right side of the heart to the lungs. In the lungs, the blood receives oxygen and releases carbon dioxide. The oxygenated blood then returns to the left side of the heart.
- **Systemic Circulation**: This is the second part of double circulation. Here, oxygenated blood is pumped from the left side of the heart to the rest of the body. After delivering oxygen and nutrients to the body tissues, the blood returns to the right side of the heart as deoxygenated blood.

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