Gravitational force acts on two objects with which of the following?

a.
mass

b.
force

c.
orbit

d.
speed

A) Mass
Gravitational Force, as stated in Newton's Law of Universal Gravitation is basically a force that attracts bodies with mass towards each other. 

I think the correct answer from the choices listed above is option A. Gravitational force acts on mass of two objects. It is force that attracts any matter that has mass. This is known as Newton's Universal Law of Gravitation. Hope this answers the question.

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.