What do bound morphemes typically include?

Bound morphemes are linguistic units that cannot stand alone as words; they must be attached to root words to convey meaning. This typically includes affixes such as prefixes or suffixes, which modify or specify the meaning of root words. For example, in the word "unhappiness," "un-" and "-ness" are bound morphemes that change the meaning of the root word "happy" by indicating negation and a state of being, respectively.

The other options do not correctly describe bound morphemes. The first option refers to free morphemes, which can stand alone as independent words. The third option speaks to complete thoughts, which are typically expressed through full sentences rather than through morphemes. The fourth option mentions words used in daily conversation, again relating more to free morphemes rather than bound morphemes, which do not function independently.