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.
Auto assembly plants employ blue collar workers. Auto mechanics are considered blue collar workers. A dish washer would be considered a blue collar job. Many blue collar jobs require experience or training in specialized tasks such as plumbing, masonry or construction.