Specifically, the oxyhemoglobin dissociation curve relates oxygen saturation (S. 2) and partial pressure of oxygen in the blood (P. 2), and is determined by what is called hemoglobin affinity for oxygen; that is, how readily hemoglobin acquires and releases oxygen molecules into the fluid that surrounds it.March 2009). The oxygenâhemoglobin dissociation curve, also called the oxyhemoglobin dissociation curve or oxygen dissociation curve (ODC), is a curve that plots the proportion of hemoglobin in its saturated (oxygen-laden) form on the vertical axis against the prevailing oxygen tension on the horizontal axis.
The Mayas believed in a world of three layers: Heaven, the middle world, and underworld. Its roots were in the underworld, its trunk in the middle world, and its branches in the highest layer of the other world.
The rise of the Maya began about 250 ce, and what is known to archaeologists as the Classic Period of Mayan culture lasted until about 900 ce. At its height, Mayan civilization consisted of more than 40 cities, each with a population between 5,000 and 50,000. Among the principal cities were Tikal, UaxactÃºn, CopÃ¡n, Bonampak, Dos Pilas, Calakmul, Palenque, and RÃ­o Bec.