The first sentence states a fact.
Bananas turn yellow as they become ripe.
It can be proved by observing bananas as they ripen.
The second sentence states an opinion.
Bananas taste great with melted chocolate.
Great shows what a person believes, thinks, or feels. Another person might have a different opinion about how bananas with melted chocolate taste.
Which sentence states a fact?
A: Bananas taste great with melted chocolate.
B: Bananas turn yellow as they become ripe.