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.
A clerical collar or clergy collar, also often known colloquially as a dog collar, is an item of Christian clerical clothing. It is a detachable collar that buttons onto a clergy shirt, being fastened by two metal studs, one attached at the front and one at the back to hold the collar to the shirt.