Value, in terms of art, is the darkness or lightness of a color. Value is one of the seven elements of art and in many circles, it is considered to be the most important. Its importance in creating the illusion of light, form, and texture in a drawing or painting cannot be denied.
However, oxygen levels can vary greatly and have a large impact on how a person is able to function. As a consequence, medical professionals have developed standards for the amount of oxygen that should be present within a personâs body. For most people, an oxygen level of 95 percent to 100 percent is considered normal.
Humans need oxygen to live, but not as much as you might think. The minimum oxygen concentration in the air required for human breathing is 19.5 percent. The human body takes the oxygen breathed in from the lungs and transports it to the other parts of the body via the body's red blood cells. Each cell uses and requires oxygen to thrive. Most of the time, the air in the atmosphere contains the proper amount of oxygen for safe breathing.