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 "What filters blood?" with the following options: 
- nephrons
 - capillaries
 - mechanical
 - four limbs
 - animals
 - organ
 - sunlight
 - mollusks


 

 nephrons        