Biology 1st Edition by Jung Choi, Jean DeSaix, Yael Avissar, Vladimir Jurukovski, Robert Wise,Connie Rye, OpenStax

تمرين 18

The first electron micrograph of a virus (tobacco mosaic virus) was produced in 1939. Before that time, how did scientists know that viruses existed if they could not see them? (Hint: Early scientists called viruses "filterable agents.")