Here's why:
* Verb: "Penetrate" is the base form of the verb, meaning to pierce or enter something.
* Past Participle: Past participles are used in various grammatical constructions:
* Perfect tenses: "He has penetrated the enemy lines."
* Passive voice: "The bullet penetrated the wall."
* Adjective: "The penetrating gaze of the detective."
So, depending on its context, "penetrated" can act as a verb (in perfect tenses and passive voice) or as an adjective.