Which sentence states a fact?

 - Mummifying a pet cat is a strange thing to do.
 - Some ancient Egyptians mummified, or preserved, their pets' bodies.
The second sentence states a fact.
Some ancient Egyptians mummified, or preserved, their pets' bodies.
It can be proved by researching ancient Eyptian culture.
The first sentence states an opinion.
Mummifying a pet cat is a strange thing to do.
Strange shows what a person believes, thinks, or feels. Another person might have a different opinion about what actions are strange.