The mass of an object causes the gravitational force exerted by that object, and an asteroid is a rock-like object with an irregular shape. Given these facts, what causes the gravitational force exerted by an asteroid among the following options: - a tree falling - flow of electrons - the shape of the asteroid - kinetic energy - solid, liquid, gas - the mass of the asteroid - the sound of the asteroid - the color of the asteroid
A:
the mass of the asteroid