Answer:
Passive voice
Explanation:
The action's target, 'Because of its vague resemblance to a bowl of popcorn, is positioned at the beginning of the sentence as the sentence's focus. The subject, the Popcorn Field, is being acted upon by the verb, knowing (in the past tense). Thus, making the subject passive. Instead, with an active voice, the subject, the Popcorn Field, is acting, knowing, on the target of action.
Passive voice: Because of its vague resemblance to a bowl of popcorn, one area of Mount Everest is known as the Popcorn Field.
Active voice: The Popcorn Field, an area of Mount Everest, is known for its vague resemblance to a bowl of popcorn.
