Question

what are the prepositional phrases in this sentence
The salmon are born in freshwater streams

Answer 1

in freshwater streams

Answer 2

At the minimum, a prepositional phrase will begin with a preposition and end with a noun, pronoun, gerund, or clause, the "object" of the preposition.

The object of the preposition will often have one or more modifiers to describe it.

Answer 3

in-preposition freshwater-modifier streams-noun