Which sentence states a fact?

 - Cheeses made from cow's milk taste better than cheeses made from sheep's milk.
 - Cheese is often made from milk that comes from cows, sheep, or goats.
The first sentence states a fact.
Cheese is often made from milk that comes from cows, sheep, or goats.
It can be proved by looking up information about cheese.
The second sentence states an opinion.
Cheeses made from cow's milk taste better than cheeses made from sheep's milk.
Better shows what a person believes, thinks, or feels. Another person might have a different opinion about which kind of cheeses tastes better.