Questions: What unit of measure is most appropriate for expressing the size of bacteria? Multiple Choice micrometer nanometer milimeter picometer

The answer is the first one: micrometer.

Explanation for each option:

1. Micrometer: This is the most appropriate unit for measuring the size of bacteria. Bacteria typically range from about 0.2 to 10 micrometers in length. The micrometer (µm) is a unit of length in the metric system equal to one millionth of a meter (10^-6 meters).

2. Nanometer: While nanometers (nm) are used to measure very small objects, such as molecules and atoms, they are generally too small for measuring bacteria. One nanometer is one billionth of a meter (10^-9 meters), which is more appropriate for structures like viruses or the components of cells, but not whole bacteria.

3. Millimeter: Millimeters (mm) are too large for measuring bacteria. One millimeter is one thousandth of a meter (10^-3 meters), which is much larger than the typical size of bacteria.

4. Picometer: Picometers (pm) are even smaller than nanometers, being one trillionth of a meter (10^-12 meters). This unit is used for measuring atomic and subatomic particles, and is far too small for bacteria.

Summary: The most appropriate unit of measure for expressing the size of bacteria is the micrometer.