Determine the use of the prepositional phrase in the following sentence.
the boy with the yellow hair ran home.
adjective
adverb

Prepositional phrase follow by a noun preposition + noun 

So in the sentence: A prepositional phrase will function as an adjective or adverb. 

As an adjective, the prepositional phrase will answer the question Which one? 

As an adverb, a prepositional phrase will answer questions such as How? When? or Where? 

Boy with the Yellow hair = adjective because it answers WHICH boy? Boy with yellow hair 

Ran home == adverb because it answers WHERE? We answer it he ran home...or ran home.

Hope that helped! :)