Fact 1: Cells are the microscopic building blocks of organisms.

Fact 2: Cells are so small that they can only be seen under a microscope.

Given the two facts above, answer the question "Cells are what, so they are the building blocks of organisms?" with the following options: 
- Most plants
 - so small
 - all matter
 - homogenous
 - so deadly
 - so fortunate
 - so big
 - bacteria


 

  so small       