Explanation: Participle phrases always use a present participle or past participle form of a verb combined with objects or modifiers to describe a noun (e.g., Passengers <u>flying in first class</u> are usually wealthy; I saw a piece of food <u>stuck in his teeth</u>). Since they can only affect nouns or noun phrases (<em>passengers</em> and <em>piece of food</em>, respectively), their function is always that of an adjective.
