As observed from the earth, the sun appears to move in an approximately circular orbit. For the motion of another planet like mercury as observed from the earth, this would:
| 1. | be similarly true. |
| 2. | not be true because the force between the earth and mercury is not inverse square law. |
| 3. | not be true because the major gravitational force on mercury is due to the sun. |
| 4. | not be true because mercury is influenced by forces other than gravitational forces. |
