live in water or a moist environment.
common in pools, ponds, lakes and streams, along ocean shores and in surface ocean waters.
range in size from microscopic to many metres long (seaweeds).
contain chlorophyll - many also contain other pigments.
food source of marine food chains.
produce 70% of all oxygen released by photosynthesis.
of minimal economic importance - used as thickeners in food (alginates) and medicines; some green, brown and red algae eaten by people from Pacific Ocean countries.
some reproduce sexually, other asexually.