Who introduced the concept of positive and negative charges?

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Historical Context**: The concept of electric charge has evolved over time, and it is important to identify the key figures in its development.

2. **Identifying the Scientist**: Benjamin Franklin is the scientist credited with introducing the concept of positive and negative charges.

3. **Franklin's Contribution**: In 1747, Franklin proposed that all neutral materials consist of an "electric fluid." He theorized that this fluid could exist in two forms: a positive fluid and a negative fluid.

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