(1) the level of carbon in the atmosphere has been consistently rising(2) Combustion, or burning, is a chemical process involving carbon , hydrogen and oxygen.(3) The search for life focuses mostly on planets with liquid water, a heat or energy source, and chemicals like carbon , hydrogen, and oxygen.(4) Then again, a diamond is only carbon (with a skin of hydrogen, one molecule thick): why shouldn't it be almost as combustible as coal?(5) The action of the micro-organisms will reduce the nitrogen, carbon and phosphate levels of the dam.(6) fossil fuel consumption and carbon emissions continued to rise(7) The plan is that these will determine the abundance and stable isotopic compositions of elements such as hydrogen, carbon , nitrogen and oxygen.(8) Proteins are composed of carbon , hydrogen, oxygen, and nitrogen; it is the presence of the last of these which distinguishes proteins from the other materials of life.(9) It is composed mostly of isotopes of hydrogen and helium and includes 60 other elements including neon, argon carbon , nitrogen, oxygen and iron.(10) a bike with a carbon frame(11) Most plants live with their heads above ground, where they pick up carbon , hydrogen and oxygen floating in the air.(12) Every source of soot, every fuel and means of burning it, has its own ratio of soot to organic carbon ; few have yet been analyzed.(13) On the Earth, it is found only in combination with other elements, such as oxygen, carbon , and nitrogen.(14) The biosphere consists of six main elements: carbon , nitrogen, phosphorus, sulphur, oxygen, and hydrogen.(15) If there is a carbon , also ask for that from the clerk and shred it when you go home.(16) For common cast iron, the main elements of the chemical composition are carbon and silicon.