Here's why:

* Base 10: The metric system uses a decimal system, meaning it's based on powers of 10. This makes calculations and conversions very straightforward.

* Prefixes: The metric system uses prefixes like "kilo" (1000), "hecto" (100), "deca" (10), "deci" (0.1), "centi" (0.01), and "milli" (0.001) to indicate multiples and submultiples of the base unit.

For example, 1 kilometer is equal to 1000 meters, not 100 meters.