Fact 1: Nephrons are the structural and functional units of the kidneys.

Fact 2: Blood is filtered in the kidney.

Given the two facts above, answer the question "Nephrons are the structural and functional units of the organ that filters what?" with the following options: 
- Light
 - Energy
 - Coffee
 - liquid
 - Air
 - Oxygen
 - Blood
 - Food


 

       Blood  