Final answer:
The prepositional phrase in the sentence provided is "with pink hair", which gives a description of the young woman.
Step-by-step explanation:
The prepositional phrase in the sentence "He saw a young woman with pink hair" is "with pink hair". This phrase begins with the preposition 'with' and ends with its object 'hair', which is modified by the adjective 'pink'.
The prepositional phrase in the sentence is "with pink hair."
A prepositional phrase consists of a preposition (in this case, "with") and its object ("pink hair"). The prepositional phrase describes the young woman and provides additional information about her appearance.
A prepositional phrase typically provides additional information about the nouns or pronouns in a sentence, in this case giving us a description of the young woman.