The tendency of two masses alone in the universe to drift together is a result of

a. fission.

b. friction.

c. fusion.

d. gravity.

It is as a result of gravity. (D)

This is as stated by Newton's law of universal gravitation. That two objects in the universe attract one another with a force that is proportional to the product of their masses and inversely proportional to the square of the distance apart.

The constant of proportionality is the Universal Gravitational Constant.

G = 6.673 * 10⁻¹¹ Nm²kg⁻²