You are presented with the question "The thing that causes objects to be pulled down on a planet was defined by which scientist?" and the following answer choices: 
- friction
 - Darwin
 - kinetic
 - the sun
 - Galileo
 - Kepler
 - energy
 - Newton

Now knowing that gravity causes objects that have mass to be pulled down on a planet and gravity was defined by Newton, choose the best answer.


 

        Newton 