In which sentence is the underlined phrase an adverb prepositional phrase? a lighthouse on howland island commemorates the disappearance of amelia earhart. amelia earhart was born in kansas in 1897. amelia earhart was the first woman to cross the atlantic by plane. amelia earhart was one of two sisters.

An adverb prepositional phrase is a phrase which adds to or modifies the adjective or adverb. This phrase must go after the word it modifies. They also expand on the circumstances surrounding an action. The adverb prepositional phrase in the above sentences can be found in the first sentence, "A lighthouse on Howland Island commemorates the disappearance of Amelia Earhart." The adverb prepositional phrase is "on Howland Island". It explains where the lighthouse is that commemorates the disappearance of Amelia Earhart. 
The second sentence "Amelia Earhart was born in Kansas in 1897". There are two possible prepositional phrases here:"in Kansas" or "in 1897".