The term carotene is used for many related unsaturated hydrocarbon substances having the formula C40Hx, which are synthesized by plants but in general, cannot be made by animals. Carotenes are photosynthetic pigments important for photosynthesis. Carotenes contain no oxygen atoms. They absorb ultraviolet, violet, and blue light and scatter orange or red light, and (in low concentrations) yellow light. Carotenes are responsible for the orange color of the carrot, for which this class of chemicals is named, and for the colors of many other fruits, vegetables and fungi (for example, sweet potatoes, chanterelle and orange cantaloupe melon).