Answer:
The first statement, Newton's rules explain how gravity affects objects, is the objective statement.
Step-by-step explanation:
An objective statement in literature is one that is does not contain any bias and is not influenced by personal feelings.
Therefor as being objective suggests that you are concerned about facts and are not influenced by personal feelings or biases, only the first statement is objective. It stated a fact without showing an inclination towards or against the message it shows, as opposed to the rest of the options which are clearly influenced by personal preferences.