Final answer:
The adverb in the sentence "Zella ate her cereal quickly" is "quickly".
Step-by-step explanation:
The adverb in the sentence "Zella ate her cereal quickly" is quickly. An adverb is a word that describes or modifies a verb, adjective, or another adverb. In this sentence, the adverb "quickly" modifies the verb "ate" by indicating how Zella ate her cereal - with speed or swiftness.
Learn more about Adverbs