Read the following statements : 

(i) Agar-agar is used to grow microbes and in the preparations of ice-creams and jellies .

(ii) Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements by space travellers. 

(iii) Porphyra, Laminaria and Sargassum are poisonous .

(iv) Algae are photosynthetic .

(v) Spirogyra is a filamentous fungus .

How many of the above statements are incorrect ?