Final answer:
The participle in the sentence is 'receding'.
Step-by-step explanation:
The participle in the sentence is receding. A participle is a verb form that functions as an adjective. In this sentence, the participle 'receding' describes the noun 'lights'. The word 'receding' is derived from the verb 'recede' and indicates that the lights of the yacht are moving away.
Learn more about participles in English language