Final answer:
Bound morphemes like suffixes and prefixes cannot stand alone and must be attached to other forms; '-ness' and 'un-' are examples.
Step-by-step explanation:
Morphemes that cannot normally stand alone and are typically attached to another form are known as bound morphemes. An example of this is the suffix -ness, which can be added to adjectives to form nouns that express a state or quality (for instance, happiness from happy), but -ness cannot stand alone as a word. Similarly, the prefix un- can attach to adjectives to give them negative or opposite meanings, as in unhealthy, but again, un- is not a standalone word.