Natural Selection - The process by which certain heritable traits that contribute to the survival and reproductive success of an organism become more widespread within a population over successive generations.⏎
Nanometer - A unit of length equal to one one-billionth (1 x 10-9) of a meter.⏎
Pathogen - A biological agent that causes disease.⏎
National Institute of Allergy and Infectious Diseases (NIAID) - Part of the U.S. Department of Health and Human Services and the National Institutes of Health, NIAID conducts and supports basic and applied research to better understand, treat, and ultimately prevent infectious, immunologic, and allergic diseases.⏎