Which of the following represents the smallest fraction of a base unit?

The correct answer is based on the metric system, which defines various prefixes that represent specific powers of ten related to base units. The prefix “milli” represents one-thousandth (1/1000) of a base unit. This makes it the smallest of the options given.

In contrast, the other prefixes represent larger fractions of the base unit. “Deci” stands for one-tenth (1/10), and “centi” stands for one-hundredth (1/100). The prefix “hecto” denotes one hundred times (100) the base unit. Therefore, when considering the options, “milli” effectively represents the smallest fraction compared to deci, centi, and hecto, making it the correct choice. Understanding these prefixes is crucial in measurements and helps in making conversions within the metric system.