Explanation

The noun phrase which would be the object in active voice sentence will become the subject phrase in passive voice sentence. Here, the 'subject' is 'acted' up on by the 'verb'.

In the given sentence, ‘you’ is subject, ‘visit’ is verb and zoo is object is in interrogative form in active voice. Now the passive voice statement has the subject ‘you’ acted up on by the verb ‘visit’.