Answers

2016-05-04T13:22:51+08:00

Living things are commonly composed of elements carbon, hydrogen, oxygen and nitrogen
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2016-05-04T14:56:35+08:00
Carbon serves as main component, hydrogen is usually attach to carbon to form the organic compound, oxygen is also important, nitrogen to form the protein of living things, iron is important for human, calcium for the bonesĀ other elements are present as trace element like zinc, potassium and iodine
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