What is an adverb prepositional phrase?

An adverb phrase adds information about a verb, adjective, or adverb. It is used to tell when, where, how, or to what extent about the Word it modifies:

Jack put the chicken in it's cage. The adverb prepositional phrase ( in it's cage ) adds information to the verb put.

Compare with

Jack is the student with the lowest grade. The adjective prepositional phrase ( with the lowest grade) modifies the noun student