What is size range of a virus?

• A. 0.2-2
• B. 2-20
• C. 0.001-0.01
• D. 0.02-0.2

Answer: (D)

Viruses are nanoscale particles, much smaller than cells. Their sizes generally span tens to a few hundred nanometers, which in micrometers is about 0.02 to 0.2 micrometers. This makes the range 0.02–0.2 micrometers the best match for typical virus sizes. For perspective, rhinoviruses are around 30 nanometers, influenza viruses about 100 nanometers, and many bacteriophages fall in the 20–200 nanometer range. In contrast, bacteria and small cells sit around hundreds of nanometers up to a few micrometers, and extremely small molecules are only a few nanometers. Therefore, the 0.02–0.2 micrometers range correctly reflects the common size scale of viruses.