Which of the following best describes a bound morpheme?

A bound morpheme is best described as a prefix or suffix that cannot exist independently. This means that it must be attached to a free morpheme (a stand-alone word) to convey meaning. For example, in the word "unhappiness," "un-" is a bound morpheme that modifies the free morpheme "happy," indicating the opposite in meaning.

This concept highlights that bound morphemes are integral to the formation of words but cannot function independently in language. Understanding bound morphemes is crucial in linguistics and language education, as it helps learners recognize how words are constructed and the roles various morphemes play in language structure and meaning.