A state of balance between continuing processes is called

• A. Concentration gradient
• B. Dynamic equilibrium
• C. Energy
• D. Membrane potential

Answer: (B)

Dynamic equilibrium describes a state where ongoing processes keep happening, but the overall conditions remain the same. In diffusion, molecules move back and forth across a membrane. When the concentrations on both sides reach an appropriate balance, the rate of movement in one direction equals the rate in the other, so there is no net change even though atoms are still moving. This balance—continuous activity with no net change—is the essence of dynamic equilibrium. In living systems, many processes operate this way to maintain stability while everything is still in motion.

A concentration gradient is the driving force that pushes movement from high to low concentration, but it isn’t itself the balanced state. Energy is the capacity to do work, not a description of a balanced ongoing process. Membrane potential is the electrical difference across a membrane, again not the balance of ongoing processes.