You are presented with the question "What vary in size as well as shape and cannot be seen without a microscope?" and the following answer choices: 
- bushes
 - matter
 - cells
 - grains
 - sand
 - bones
 - apples
 - small

Now knowing that cells vary in size as well as shape, but all cells are very small and most cells are too small to be seen without a microscope, choose the best answer.


 

   cells      