Fact 1: Agasoline lawn mower converts gasoline into motion.

Fact 2: Small engines, such as in lawn mowers, pollute at a high rate.

Given the two facts above, answer the question "converting gasoline into motion cause what" with the following options: 
- Dehydration
 - elections
 - global debt
 - friction
 - dangerous
 - pollution
 - Firecrackers
 - traffic jams


 

      pollution   