Give the aim of excretion.

Explanation

### Step-by-Step Solution:

1. **Definition of Excretion**:
- Excretion is the process of eliminating unwanted substances from the body. It is a vital physiological function that helps maintain the internal environment of an organism.

2. **Aim of Excretion**:
- The primary aim of excretion can be summarized into three key purposes:

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