In short
Algae are simple plant-like organisms that make food by photosynthesis and live mostly in water. They have no true roots, stems or leaves.
They are grouped by their pigments. Green algae (Chlorophyceae) contain chlorophyll a and b and store starch. Brown algae (Phaeophyceae) contain fucoxanthin and include large seaweeds such as kelps. Red algae (Rhodophyceae) contain phycoerythrin and live in deep, warm water. Algae reproduce by fragmentation, by spores, and by sexual reproduction. They are the source of much of the oxygen in the air.
Spirogyra is a green alga that forms slimy green threads in ponds. Laminaria is a brown alga, and Porphyra is a red alga eaten as food.
Also searched as: red brown and green algae, reproduction in algae.
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