Select the correct passive form of the given sentence.

She has learned many lessons in this camp.

Many lessons have been learned by her in this camp.

The correct passive form of the given sentence is Many lessons have been learned by her in this camp.

The active voice of the sentence is "She has learned many lessons in this camp." This sentence is in the present perfect tense, which is used to describe an action that has happened in the past and is still relevant to the present. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the past participle of the main verb. In this case, the subject of the active sentence is "she" and the main verb is "learn." The past participle of "learn" is "learned." So, the passive form of the sentence is "Many lessons have been learned by her in this camp."

The other options are incorrect because:

• Many lessons has been learned by her in this camp." This sentence is in the present perfect tense, but the subject of the sentence is plural. The subject of the sentence should be singular to match the verb.
• Many lessons are being learned by her in this camp." This sentence is in the present progressive tense, which is used to describe an action that is happening now but is not finished. However, the action of learning lessons in the camp has already happened.
• Many lessons were learned by her in this camp." This sentence is in the simple past tense, but the subject of the sentence is plural. The subject of the sentence should be singular to match the verb.