Which metric prefix represents a factor of one?

• A. kilo-
• B. none (the base unit)
• C. milli-
• D. centi-

Answer: (B)

Verified step by step guidance

1. Understand that metric prefixes are used to denote powers of ten that multiply the base unit. For example, 'kilo-' means 10^3, 'milli-' means 10^-3, and 'centi-' means 10^-2.
2. Recall that the base unit itself (such as meter, gram, or liter) represents a factor of one, meaning it is not multiplied or divided by any power of ten.
3. Recognize that no prefix corresponds to a factor of one; the absence of a prefix means the quantity is exactly the base unit.
4. Therefore, the correct answer to the question 'Which metric prefix represents a factor of one?' is that there is no prefix—it is simply the base unit without any prefix.
5. Summarize that metric prefixes modify the base unit by powers of ten, but the base unit alone inherently represents a factor of one.