The cyanobacteria are unicellular, colonial or filamentous , freshwater/marine or terrestrial algae. Does that mean that the algae will be either unicellular or colonial or filamentous and that it will be either freshwater or marine or terrestrial ? Please explain the terms.

Dear student,
Cyanobacteria can be unicellular or colonial (colony are usually surrounded by gelatinous sheath, colonies can also contain filamentous cyanobacteria) or filamentous and it can either form bloom in freshwater (water naturally occurring on earth's surface which is not salty) or marine (sea water which is salty) water or can also be found in terrestrial habitat. It is found in almost all terrestrial and aquatic habitat.
Single celled cyanobacteria is called unicellular cyanobacteria.
Cyanobacteria can also form colonies i.e form groups of cyanobacteria surrounded by sheath.
Filamentous form includes chains of cyanobacteria.
Terrestrial means land.
Habitat means natural place to live in.

Regards