which sentence is in passive voice? by this time tomorrow, a wrecking ball will have demolished the historic…

Brief Explanations:

In the passive - voice, the subject of the sentence receives the action. In "By this time tomorrow, the theater will have been demolished by a wrecking ball", the subject "the theater" is receiving the action of being demolished. In "By this time tomorrow, a wrecking ball will have demolished the historic theater downtown", the subject "a wrecking ball" is performing the action.

Answer:

By this time tomorrow, the theater will have been demolished by a wrecking ball.