You are presented with the question "Something that can cause many human diseases can be what?" and the following answer choices: 
- deadly and devastating
 - Disease textbooks
 - harmful substances
 - Microscopic organisms
 - Human thoughts
 - destroying life
 - Human emotions
 - Created by a natural process.

Now knowing that viruses cause many human diseases and human viruses are created by natural process, choose the best answer.


 

        Created by a natural process. 