Here's a problem to solve: One 7.0 kg bowling ball is lifted to a storage shelf 1.0 m above the floor. A second 7.0 kg ball is lifted to a storage shelf 2.0 m above the floor. Which of the following best explains why the measured force of gravity on each ball is nearly identical?

Among the 4 following options, which is the correct answer?

- A: The final potential energy of each ball increased.
 
- B: The amount of work required to lift each ball is identical.
 
- C: The distance of each ball from Earth's center of mass is almost identical.
 
- D: The gravitational force of each ball on the other cancels out the force of Earth's gravity.
 