Fact 1: Gravity causes objects that have mass to be pulled down on a planet.

Fact 2: Another name for Mars is the Red Planet.

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


 

     objects that have mass    