Which sentence states a fact?

 - Rainforests supply one out of every four ingredients used in modern medicine.
 - People rely too heavily on the resources that rainforests provide.
The second sentence states a fact.
Rainforests supply one out of every four ingredients used in modern medicine.
It can be proved by looking up where medicines come from.
The first sentence states an opinion.
People rely too heavily on the resources that rainforests provide.
Too heavily shows what a person believes, thinks, or feels. Another person might have a different opinion about how much people should rely on these resources.