Fact 1: Chemical splashing can cause harm to humans.

Fact 2: Ozone is harmful to humans and crops.

Given the two facts above, answer the question "What can harm crops?" with the following options: 
- Nematoda
 - influenza
 - vehicles
 - burning
 - chemicals
 - smallpox
 - Roundworms.
 - flooding


 

     chemicals    