I. Unicellular. Colonial, filamentous, marine or terrestrial forms
II. The colonial , filamentous, marine or terrestrial forms
III. Some can fix atmospheric nitrogen in specialised cells called heterocysts
IV. They often form blooms in water bodies.
these above characters are seen in

Options

A. Archaebacteria
B. Cyanobacteria
C. Chrysophytes
D. Dinoflagellates

Answer

B