Final answer:
The word 'quickly' in the sentence is an adverb that describes how she ran.
Step-by-step explanation:
The word 'quickly' in the sentence 'She ran quickly to catch the bus' is an adverb. Adverbs are words that modify verbs, adjectives, or other adverbs. They provide information about how, when, where, or to what extent an action is performed. In this sentence, 'quickly' describes how she ran.
Learn more about Parts of Speech