Final answer:
A modifier is a word or phrase that provides a description and modifies other words in a sentence. Adjectives modify nouns, while adverbs modify verbs.
Step-by-step explanation:
A modifier is a word or phrase that provides a description and modifies other words in a sentence. In the case of nouns, adjectives act as modifiers by describing or providing more information about the noun. For example, in the sentence 'I need to find an affordable car,' the word 'affordable' is an adjective that modifies the noun 'car' by describing its quality.
On the other hand, adverbs are modifiers that describe verbs. They provide information about the time, place, reason, or manner in which an action is performed. For instance, in the sentence 'Pierre quickly ran through the main points of his argument,' the adverb 'quickly' modifies the verb 'ran' by describing how Pierre ran through the points.