An externality is defined as a benefit or cost that is imposed on a third party, such as society, other than the producer or consumer of a good or service, or, more simply, an economic side effect. The more of a product that is consumed or produced, the more of an externality that results.
Arteries carry oxygenated blood (with the exception of the pulmonary artery and umbilical artery). Veins carry deoxygenated blood (with the exception of pulmonary veins and umbilical vein).
The typical artery carries oxygenated blood while the typical vein carries deoxygenated blood carrying carbon dioxide from the cells. However, the pulmonary arteries and ve â¦ ins connect the heart to the lungs, and their contents are the reverse.he are both blood vessels, but have different functions. Arteries carry blood away from the heart and the veins bring blood to the heart. Arteries carry blood with more press â¦ ure than veins, so they are thicker and more muscular.