Equilibrium is best defined as a state of

Equilibrium is best defined as a state of physical balance.

Explanation:

Physical balance is a term used to describe the situation in which the forces acting on a body on its internal and external side are equal. That is, the resulting force in this body is zero. In this case, we can say that this body is in a situation of equilibrium, where all things are in harmony and nothing is standing out or being ignored. That way all the factors that allow a body to function will function normally in a regulated and efficient way.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .