You are presented with the question "How can viruses make copies of themselves?" and the following answer choices: 
- A compound that donates proton
 - attach themselves to cells
 - have sex with another virus
 - distances themselves from cell
 - attach themselves to viruses
 - it needs them
 - rapid expansion
 - By wind and rain

Now knowing that viruses cannot reproduce by themselves and viruses attach themselves to cells and reproduce, choose the best answer.


 

  attach themselves to cells       