The further objects are away from each other, the smaller the gravitational force.  The sun exerts gravitational force on all the planets, which has a lower gravitational force earth or mars?
mars

Electrons at lower energy levels, which are closer to the nucleus, have less energy.  An electron with a low energy level will have energy that is lower or higher?
lower

Less massive objects also have less gravity than more massive objects.  Mary was comparing the size of two objects. If she examined an orange and compared it with a watermelon, which would generate more gravity orange or watermelon?
watermelon