Fact 1: The mass of an object causes the gravitational force exerted by that object.

Fact 2: Gravity accelerates mass.

Given the two facts above, answer the question "What accelerates an object?" with the following options: 
- transportation technology
 - chemical messengers
 - kinetic energy
 - electromagnetic energy
 - gravitational force
 - flow of electrons
 - a hydraulic system
 - heat energy


 

     gravitational force    