1 Most cases of COPD, and therefore emphysema, are caused by cigarette smoking. 2  Emphysema is rarely caused by a congenital condition known as Î±1-antitrypsin deficiency, for which there is a lab test. 3  Shortness of breath and cough are the main symptoms of emphysema.
Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth.
Other organisms such as algae and plants that use photosynthesis to extract energy from the sun along with carbon dioxide and water to produce sugars are called autotrophs. Certain types of bacteria use chemosynthesis to couple the transformation of organic molecules into from their energy with inorganic molecules.