In the sentence ‘She sings beautifully,’ what part of speech is ‘beautifully’?

In the sentence 'She sings beautifully,' the word 'beautifully' is an adverb. Adverbs modify verbs, adjectives, or other adverbs, explaining how, when, where, or to what extent something is done. Here, 'beautifully' describes the manner in which she sings, answering the question 'how does she sing?' Unlike adjectives that modify nouns, adverbs like 'beautifully' often end in 'ly' and enhance the meaning of the verbs they accompany to provide more detail.