<prompt> Beta phage is seen in -Bacillus anthracisCorynebacterium diphtheriaeClostridium botulinumPeptostreptococci  <response>: Ans. is b i.e., Corynebacterium diphtheriae o The toxigenicity of the diphtheria bacilli depends on the presence in it of corynephages tox . Nontoxigenic strains may be rendered toxigenic by infecting them with beta phage or some other larger phage. This is known as lysogenic conversion or phage conversion. 