it's been a while meaning, it's been a while definition | English Cobuild dictionary. been. 1 Been is the past participle of be. 2 verb If you have been to a place, you have gone to it or visited it. He's already been to Tunisia, and is to go on to Morocco and Mauritania...
Carbon dioxide is a by-product of respiration ] and combustion combustion: Combustion is the process of burning by fire. . Green plants remove carbon dioxide from the atmosphere by photosynthesis. Living organisms-including all plants and animals-release energy from their food using respiration.Respiration and combustion-burning-both release carbon dioxide into the atmosphere.These processes form a carbon cycle in which the proportion of carbon dioxide in the atmosphere remains about the same.The animation should help you to understand how the cycle works.espiration and combustion-burning-both release carbon dioxide into the atmosphere. These processes form a carbon cycle in which the proportion of carbon dioxide in the atmosphere remains about the same.
Let us consider the results of this process: Photosynthesis and oxygen In carrying out photosynthesis, plants absorb the carbon dioxide in the air (CO2), a gas that human beings cannot use, and break it down into oxygen (O2).