Examples of homeostasis include the regulation of body temperature, the pH of extracellular fluid, or the concentrations of sodium, potassium and calcium ions as well as that of glucose in the blood plasma, despite changes in the environment, diet, or level of activity.
Blue-collar workers perform labor jobs and typically work with their hands. The skills necessary for blue-collar work vary by occupation. Some blue-collar occupations require highly skilled personnel who are formally trained and certified.
Blue-collar Federal workers have been paid according to local prevailing private sector rates since the Civil War. Until 1965, each Federal agency had authority to determine local prevailing rates and establish wage area boundaries for its employees.