Which of the following is the most appropriate unit for expressing the speed of a snail ?

Options

A. `km//s`
B. `m//s`
C. `cm//s`
D. `mm//s`

Answer

To determine the most appropriate unit for expressing the speed of a snail, we can follow these steps:

### Step 1: Understand the speed of a snail
A snail is known to be one of the slowest creatures on earth. Its speed is typically very low, often measured in millimeters per second.

### Step 2: Analyze the options given
The options provided for the units of speed are:
1. Kilometer per second (km/s)
2. Meter per second (m/s)
3. Centimeter per second (cm/s)
4. Millimeter per second (mm/s)

### Step 3: Consider the scale of the speed
Since snails move very slowly, using larger units like kilometers or meters per second would yield very small decimal values. For example, if a snail moves at 1 mm per second, this would be:
- 1 mm/s = 0.001 m/s (which is a very small number)
- 1 mm/s = 0.000001 km/s (even smaller)

### Step 4: Evaluate the most suitable unit
Using millimeters per second (mm/s) allows us to express the speed of a snail in whole numbers rather than decimals. For instance, if a snail moves at a speed of 1 to 2 mm per second, it is straightforward and easy to understand.

### Conclusion
The most appropriate unit for expressing the speed of a snail is **millimeter per second (mm/s)**.

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