Q: 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, what accelerates an object?

Available options: [i] transportation technology; [ii] chemical messengers; [iii] kinetic energy; [iv] electromagnetic energy; [v] gravitational force; [vi] flow of electrons; [vii] a hydraulic system; [viii] heat energy;
The answer is:
[v]