Which sentence states a fact?

 - A shark's skeleton is made of cartilage, not bone.
 - Sharks are the most savage hunters in all of nature.
The second sentence states a fact.
A shark's skeleton is made of cartilage, not bone.
It can be proved by reading a book about sharks.
The first sentence states an opinion.
Sharks are the most savage hunters in all of nature.
Most savage shows what a person believes, thinks, or feels. Another person might have a different opinion about what makes an animal savage.