Black tea is one of the most common teas known to mankind. The teas come from the same plant, but each variety is processed differently. The tea plant is actually a tree and grows only in certain climates. The world's major tea growing areas are in the higher elevations of China, Japan, India, Sri Lanka and East Africa. After the evergreen shoots of black tea are picked, they are withered, rolled, fermented and dried. The high levels of antioxidants in black tea have been found to not only improve artery function but also to lower the rates of cancers. They have the ability to stop the oxidation which causes damage to DNA and turn normal cells into cancer cells.