Answer:
near the edge
Step-by-step explanation:
A preposition is a word that shows a relationship of a noun or a pronoun or connects a noun or a pronoun with other part of the sentence. On the other hand, Phrases are groups of words often without a finite verb forming part of a sentence.
Now a prepositional phrase contains a preposition and its object. It is often referred to as a "non - headed phrase", because none of its constituents solely functions as the head of the phrase instead, the structure of the phrase is divided into two functional components ;
the preposition and its complement/object. The preposition in a prepositional phrase can be a single word or multiple words. Similarly , its complement or object can be an adverb or a noun phrase.
In the given question, we are to identify the prepositional phrase in the sentence :
James often waits near the edge of the platform for the train.
So, near the edge is the prepositional phrase.