Answer:
loosened
Explanation:
A participle is a verbal type acting as an adjective in a sentence. There are two types of participles: the present participle, which ends in -ing, like winning, and the past participle which is formed from the past tense of a verb, and therefore they usually have the endings -ed, -d, -t, -en, or -n, such as swollen and broken.
In the sentence, “loosened” is a participle because it works as an adjective describing or giving more information about the noun “rocks.” Furthermore, it is a past participle because it is formed from the past tense of the verb “loose.”
