What is meant by Unit? What is the importance of a unit?

Explanation

### Step-by-Step Solution

**Step 1: Definition of a Unit**
A unit is a standard measurement used to quantify physical quantities. It provides a reference point for measuring and expressing the magnitude of a physical quantity. For example, distance can be measured in units such as meters or centimeters, mass in grams or kilograms, and time in seconds or hours.

**Step 2: Importance of Units**
Units are crucial for several reasons:
1. **Expressing Measurements**: Units allow us to express the measurements of physical quantities in a standardized way. For example, stating that a distance is 5 meters provides a clear understanding of the measurement.
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