Fact 1: Cells cannot survive without oxygen.

Fact 2: Cells are the units of function in living things.

Given the two facts above, answer the question "what cannot survive without oxygen?" with the following options: 
- animals
 - tanks
 - an organism's body
 - living things
 - hydrogen
 - space
 - Veins and arteries.
 - mammals


 

    living things     