定義： This organism produces this material or substance, either during its life or after death. A produces B if some process that occurs in A has output B.
定義： A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
定義： substance or combination of substances that may be administered to human beings (or animals) for treating or preventing disease, or with the intent to make a medical diagnosis or to restore, correct or modify physiological functions.
