Which metric unit is most appropriate for expressing the size of human skin cells?

• A. nanometer (nm)
• B. micrometer (µm)
• C. millimeter (mm)
• D. centimeter (cm)

Answer: (B)

Verified step by step guidance

1. Understand the typical size range of human skin cells, which is generally on the order of tens of micrometers.
2. Recall the metric units and their relative sizes: 1 centimeter (cm) = 10 millimeters (mm), 1 millimeter (mm) = 1000 micrometers (\mu m), and 1 micrometer (\mu m) = 1000 nanometers (nm).
3. Compare the size of human skin cells to these units: since skin cells are about 10 to 30 micrometers, expressing their size in micrometers (\mu m) is most convenient and clear.
4. Recognize that using nanometers (nm) would result in very large numbers, and millimeters (mm) or centimeters (cm) would be too large and less precise for cell size.
5. Conclude that the micrometer (\mu m) is the most appropriate metric unit for expressing the size of human skin cells.