Root plant to fuel the process. In return, the plant takes nitrogen compounds produced from ammonia by the bacteria. The term root crops refers to any edible underground plant structure, but many root crops are actually stems, such as potato tubers. Edible roots include cassava, sweet potato, beet, carrot, rutabaga, turnip, parsnip, radish, yam and horseradish. Spices obtained from roots include sassafras, angelica, sarsaparilla and licorice. Sugar beet is an important source of sugar. Yam roots are a source of estrogen compounds used in birth control pills. The fish poison and insecticide rotenone is obtained from roots of "Lonchocarpus" spp. Important
Root beer root beer in cold, frosty mugs. IBC Root Beer is another brand of commercially produced root beer that emerged during this period and is still well-known today. Safrole, the aromatic oil found in sassafras roots and bark that gave traditional root beer its distinctive flavour, was banned for commercially mass-produced foods and drugs by the FDA in 1960. Laboratory animals that were given oral doses of sassafras tea or sassafras oil that contained large doses of safrole developed permanent liver damage or various types of cancer. While sassafras is no longer used in commercially produced root beer and is sometimes