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.
A fact is something that can be proved to be true.
The month of July has more days than the month of June.
This is a fact. It can be proved by looking at a calendar and counting the number of days in each month.
An opinion is something that a person believes, thinks, or feels. An opinion cannot be proved true.
July is a better month than June for camping.
This is an opinion. People may have different opinions about which month is "better" for camping.
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.