Chlorella is a fresh water, single-celled algae that grows in fresh water. Chlorella emerged over 2 billion years ago, and was the first form of a plant with a well-defined nucleus. Because Chlorella is a microscopic organism, it was not discovered until the late 19th century, deriving its name from the Greek, "chloros" meaning green and "ella" meaning small. In fact that chlorella contains the highest amount of chlorophyll of any known plant. Chlorella is a fresh water, single-celled algae that grows in fresh water. Chlorella emerged over 2 billion years ago, and was the first form of a plant with a well-defined nucleus. Because Chlorella is a microscopic organism, it was not discovered until the late 19th century, deriving its name from the Greek, "chloros" meaning green and "ella" meaning small. In fact that chlorella contains the highest amount of chlorophyll of any known plant. Chlorella is now used as an adjunct supplement during radiation treatment for cancer. Its abundance of chlorophyll is known to protect the body against ultraviolet radiation. It is a nutrient-dense superfood that contains 60% protein, 18 amino acids (including all the essential amino acids), and various vitamins and minerals. One of its unique properties is a phytonutrient called CGF.