Question

which is one millionth of a meter?
millimeter
micrometer
decimeter
microliter

Explanation:

To determine which is one millionth of a meter, we analyze each option:

• Millimeter: 1 millimeter = \(10^{-3}\) meters (one thousandth of a meter), not one millionth.
• Micrometer: 1 micrometer = \(10^{-6}\) meters, which is one millionth of a meter (since \(10^{-6}=\frac{1}{10^{6}}=\frac{1}{1000000}\)).
• Decimeter: 1 decimeter = \(10^{-1}\) meters (one tenth of a meter), not one millionth.
• Microliter: This is a unit of volume (liters), not length, so it's irrelevant to the question about meters.

Answer:

B. Micrometer