Algae are a group of plantlike organisms that live near the surface of ponds, lakes, and oceans.
Algae are like plants because they are able to use the sun's energy to make their own food.
Organisms that can use the suns energy to make their own food are called autotrophs.
Algae are considered eukaryotic organisms because they have complex cell structure and a membrane bound nucleus. Algae can be either unicellular or multicellular.
Many creatures depend on algae as a food source and as a major oxygen producer for the Earth's atmosphere.