You are presented with the question "what part of a planet causes the pull of gravity on that planet?" and the following answer choices: 
- solid, liquid, gas
 - layers of fat
 - barrel-shaped
 - our star
 - amount of matter
 - an external framework
 - hydrogen and oxygen
 - It expands

Now knowing that the mass of a planet causes the pull of gravity on that planet and mass, the amount of matter in an object, is measured in grams, choose the best answer.


 

     amount of matter    