Final answer:
Distance decay describes the diminishing importance and eventual disappearance of a phenomenon with increasing distance from its origin.
Step-by-step explanation:
The term "Distance decay" refers to option b) The diminishing in importance and eventual disappearance of a phenomenon with increasing distance from its origin. This concept describes how the intensity or regularity of an object, idea, or behavior decreases as it moves further away from its source. It demonstrates the tendency for things to become less similar as their distance from each other increases.
For example, a cultural trait may be highly prevalent near its place of origin, but as distance increases, it gradually fades away or becomes less common. This can be observed in the spread of languages, customs, and technologies.