5. How many types of viruses cause influenza? A. Five types:

Last updated: 7/23/2022

5. How many types of viruses cause influenza? A. Five types: A, B, C, D, and E B. 144 different subtypes: from H1N1 to H9N16. C. Three types: A, B, and C D. More than 200 types E. None of the above