These include natural and organic methods to control harmful insects and weeds instead of using chemicals.

VOA: special.2009.07.14

Antibiotics are chemicals, usually small organic molecules that will kill micro-organisms like bacteria.

抗生素是一类化学物质,它们通常是小分子有机物,能够杀死细菌这样的微生物

耶鲁公开课 - 生物医学工程探索课程节选

Students grow organic food and use as little fossil fuels and chemicals as possible.

VOA: special.2009.04.14