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The smallest chemical unit of matter


Two or more atoms linked together to make a substance with unique properties


The process by which green plants and some other organisms use the nergy of sunlight and simple chemicals to produce their own food


The sum total of all processes in an organism that convert energy and matter from outside sources and use that energy and matter to sustain the organism's life functions


Special structures that allow living organisms to sense the conditions of their internal or external enviorment


The smallest unit of life

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