In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

A trend or a fad is a type of behavior that develops in a large population .
A fad , trend , or craze is any form of collective behavior that develops within a culture , a generation or social group in which a group of people enthusiastically follow an impulse for a finite period .