You are presented with the question "What requires a microscope in order to be seen?" and the following answer choices: 
- fungi
 - cells
 - mildew
 - gasoline
 - fungus
 - matter
 - telescopes
 - sunlight

Now knowing that cells vary in size as well as shape, but all cells are very small and an embryo is so small that it requires a microscope in order to be seen, choose the best answer.


 

  cells       