Final answer:
An adverb is a part of speech that describes or modifies a verb, adjective, or another adverb and can answer questions such as how, when, where, to what extent, and how long.
Step-by-step explanation:
An adverb is a part of speech that can answer the questions "How?", "When?", "Where?", "To what extent?", and "How long?". It describes or modifies a verb, adjective, or another adverb. For example, in the sentence 'She ran quickly to catch the bus', the word 'quickly' is an adverb because it describes how she ran.
Learn more about Adverbs