001  0a) If the cells have structures inside (organelles), then it is not a cyanobacterium.

002

003  0b) If the cells do not have organelles, then go to Couplet A1/A2, Lines 006, 008.

004

Fig. 0.1) Observe below, alga 1 and 2 have organelles.  Therefore, they are

not cyanobacteria.  Algae 3 does not have organelles.  Therefore, they are

cyanobacteria.