Fact 1: Carpooling decreases the amount of cars used to travel to a place.

Fact 2: Arrange carpools to conserve fuel.

Given the two facts above, answer the question "What can reduce fuel usage?" with the following options: 
- airplanes
 - adding heat
 - trains
 - evaporation
 - buses
 - Metling snow
 - car pools
 - exercise


 

       car pools  