Final answer:
A plaque is composed of bacteriophage and dead bacteria. When a bacteriophage infects a bacterial cell, it replicates inside the cell and eventually causes the cell to burst, releasing new phages and causing the formation of a clear plaque on the bacterial lawn.
Step-by-step explanation:
A plaque is composed of E) bacteriophage and dead bacteria. A plaque is a clear area on a bacterial lawn caused by the viral lysis of host cells. When a bacteriophage infects a bacterial cell, it replicates inside the cell and eventually causes the cell to burst, releasing new phages and causing the formation of a clear plaque on the bacterial lawn.