Select a category above to classify viruses according to shared characteristics. Select any virus below to explore its structure and biology. The envelope contains viral proteins embedded in it.

How did viruses evolve? Are they a streamlined form of something that existed long ago, or an ultimate culmination of smaller genetic elements joined together? Aa Aa Aa The evolutionary history of ...

See virus and antivirus program. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.