Question

a single red blood cell has an average diameter of 7.5 × 10^(-6) meters. which two units of measurement are most appropriate to use when discussing this size? millimeters and centimeters micrometers and nanometers kilometers and meters liters and grams

Explanation:

1. Recall the metric - prefix conversions:

• 1 micrometer ($\mu m$) = $10^{- 6}$ meters. A red - blood cell with a diameter of $7.5\times10^{-6}$ meters is 7.5 micrometers.
• 1 nanometer ($nm$) = $10^{-9}$ meters. So, $7.5\times10^{-6}$ meters is $7.5\times10^{3}$ nanometers.
• Millimeters ($1\ mm=10^{-3}\ m$) and centimeters ($1\ cm = 10^{-2}\ m$) are too large for this measurement. Kilometers ($1\ km = 10^{3}\ m$) and meters are also much too large. Liters and grams are units of volume and mass respectively, not length.

Answer:

B. Micrometers and nanometers