How many types of bacteriophage are there ?
--- myoviridae --- bacteriophage mu --- bacteriophage p1 --- bacteriophage p2 --- bacteriophage t4 --- podoviridae --- bacteriophage n4 --- bacteriophage p22 --- bacteriophage t3 --- bacteriophage t7 --- siphoviridae --- bacteriophage hk022 --- bacteriophage lambda