Why is the process taking place in proximal convoluted tubule called reabsorption? What is the significance of this process?

Explanation

### Step-by-Step Solution

1. **Understanding the Proximal Convoluted Tubule (PCT)**:
- The proximal convoluted tubule is a part of the nephron in the kidney where the initial stages of urine formation occur. It plays a crucial role in the reabsorption of essential substances.

2. **Definition of Reabsorption**:
- Reabsorption is the process by which substances that have been filtered out of the blood (into the nephron) are taken back into the bloodstream. This process is essential for maintaining the body's balance of fluids and electrolytes.

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