What is the full name of the metric prefix sequence used for length units (Kilometers, Hectometers, Deka-Meters, G. and L., Decimeters, Centimeters, Millimeters)?

• A. Kilometers-Hectometers-Deka-Meters(G. and L.)-Decimeters-Centimeters-Millimeters
• B. Kilograms-Hectometers-Deka-Meters-G. and L.-Decimeters-Centimeters-Millimeters
• C. The prefix sequence used for time measurements
• D. A system of weight prefixes

Answer: (A)

Metric prefixes scale base units by powers of ten, and for length the base unit is the meter. The common sequence around the meter is kilo- (10^3), hecto- (10^2), deka- (10^1) before the base, and deci- (10^-1), centi- (10^-2), milli- (10^-3) after. This is why the length units shown—kilometer, hectometer, dekameter, meter, decimeter, centimeter, millimeter—fit together as a coherent decimal scale. The same prefixes can also be used with other units (for example, liters for volume, or gigameters for very large distances).

So the full name of this sequence is the SI metric prefixes as applied to length. The other options either refer to mass or time, or mix up units, and thus don’t describe the length-prefix sequence.