Fact 1: Brain cells die quickly if their oxygen supply is cut off.

Fact 2: Here, the lungs supply the blood with oxygen.

Given the two facts above, answer the question "What will die without a supply of blood?" with the following options: 
- plants
 - organs
 - brain cells
 - athletes
 - humans
 - species
 - critical organs
 - mushrooms


 

   brain cells      