Which sentence states a fact?

 - In most respects, stars are more interesting than planets.
 - In terms of size and age, the Sun is an average star.
The first sentence states a fact.
In terms of size and age, the Sun is an average star.
It can be proved by looking up information about the Sun and other stars.
The second sentence states an opinion.
In most respects, stars are more interesting than planets.
More interesting shows what a person believes, thinks, or feels. Another person might have a different opinion about which are more interesting.