Explain why anxiety is described as an abnormal emotional reaction only when it is out of proportion to, or persists beyond, whatever provoked it, rather than simply by its presence.

Some degree of apprehension in the face of genuine uncertainty or threat is an entirely normal and adaptive response, so anxiety only becomes clinically significant when its intensity, duration, or persistence no longer fits the situation that provoked it. A feeling of unease that is proportionate to a real, ongoing difficulty, and that resolves once the difficulty passes, is not itself pathological. What marks anxiety as abnormal is when it is disproportionate to any real threat, or continues well beyond the situation that triggered it, or occurs without any identifiable trigger at all — at which point it reflects a disturbance in its own right rather than an understandable reaction to circumstances.