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.
(or Plantae). Virtually all other living creatures depend on plants to survive. Through photosynthesis, plants convert energy from sunlight into food stored as carbohydrates. Because animals cannot get energy directly from the sun, they must eat plants (or other animals that have had a vegetarian meal) to survive.irtually all other living creatures depend on plants to survive. Through photosynthesis, plants convert energy from sunlight into food stored as carbohydrates. Because animals cannot get energy directly from the sun, they must eat plants (or other animals that have had a vegetarian meal) to survive.