Algae are beneficial to human in different ways as follows;
Laminaria, Porphyra and Sargassum are used as food supplements. Algae perform photosynthesis because of which they enhance the amount of oxygen in their surrounding and are also involved in carbon fixation. Algin and Carrageen are hydrocolloids which have the capacity to hold water and are produced by brown and red algae respectively. Agar is a gelatinous substance produced by Gelidium and Gracilaria used as culture medium in laboratories. Therefore, third statement is incorrect and all other statements are true.

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