You are presented with the question "Gravity causes what to be pulled down on Mars?" and the following answer choices: 
- space
 - living things
 - hydrogen and oxygen
 - massless objects
 - objects that have mass
 - fissures of hot, acidic water
 - nothingness
 - principals of aerodynamics

Now knowing that gravity causes objects that have mass to be pulled down on a planet and another name for Mars is the Red Planet, choose the best answer.


 

     objects that have mass    