What concept describes a system in a state of change yet in equilibrium?

The concept of a system in a state of change yet in equilibrium is best described by dynamic equilibrium. Dynamic equilibrium refers to a situation in which a system is in a constant state of flux, with ongoing processes and changes happening, but the overall system maintains a stable condition. This means that while components of the system may be in motion or experiencing changes, the system as a whole does not drift away from its equilibrated state.

In this context, dynamic equilibrium highlights the continuous interactions and adjustments within a system that allow it to adapt to new conditions while still achieving balance. This concept is often applicable in various fields, such as biology, ecology, and economics, where systems must react and evolve over time yet still function effectively within a certain range of conditions.

The other options, while related to stability and change in systems, do not capture the essence of a system that is actively changing while still remaining in a state of balance. Static equilibrium refers to a condition where a system is at rest and remains unchanged. Linear stability generally relates to systems that return to equilibrium after small disturbances but do not accommodate the continuous changes characteristic of dynamic equilibrium. Dynamic complexity, while suggesting that systems can behave in unpredictable ways, does not specifically focus on the maintaining of equilibrium amidst change.