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. Refers to employees whose job entails (largely or entirely) physical labor, such as in a factory or workshop. For a piece of work to be termed blue collar, it should be directly related to the output generated by the firm, and its end result should be identifiable or tangible. Historically, in the West, manual workers wore blue shirt collars but clerical workers wore white. See also white collar.