What characteristic best describes a reversible process?

A reversible process is one in which a system can return to its initial state after a change has occurred, and this can be achieved without any net change to the system or the surroundings. The key characteristic of a reversible process is that it allows for both the forward and backward transitions between states, maintaining equilibrium and requiring infinitesimally small changes to move between those states.

When a process is reversible, it implies that the changes can be undone as if they never happened, thus allowing the system to be returned to its original condition without any leftover effects or energy dissipation. This characteristic illustrates the idea of dynamic balance, where every process can be reversed and rerun without any alteration to either the state of the system or the environment.

Considering this, the definition implies that a reversible process can indeed be both redone and undone, emphasizing the fluidity and symmetry of these transitions in thermodynamic and physical systems.