Answer and explanation:
Greenhouse gases are carbon dioxide, water vapor, fluorinated gases, nitrous oxide, methane, and others. Carbon dioxide enters the atmosphere by respiration of plants, animals, and microbes. Plants also remove carbon dioxide during photosynthesis. The net result is that plants remove more carbon dioxide than they contribute. Microbes and fungi that decompose plants and animals also return the carbon to the atmosphere as carbon dioxide. These are all ways nature cycles carbon. Humans contribute carbon dioxide to the atmosphere when we burn wood, solid waste, and fossil fuels. When forests are burned to clear land, not only does the burning release carbon dioxide, but it eliminates trees that would otherwise be removing carbon dioxide by photosynthesis. Most of the human contribution is from burning fossil fuels in electrical power plants that burn coal or natural gas and in vehicles that run on petroleum products. Other industrial processes also contribute carbon dioxide to the atmosphere, but to a lesser extent.