31. The protection that water in the body affords to the brain and other vital organs is an example of its function as a

A. lubricant.

B. metabolic agent.

C. universal solvent.

D. protective cushion.

32. What is typically the first physical sign of dehydration?

A. thirst

B. fatigue

C. rapid pulse

D. low urine output

33. What is hypokalemia?

A. a form of water intoxication

B. an extreme form of dehydration

C. a very low level of blood potassium

D. a very low level of sodium in the blood

34. Consuming too much _________ can cause hyponatremia.

A. salt

B. water

C. alcohol

D. potassium

35. What can result from hypovolemia?

A. fainting

B. diarrhea

C. rapid breathing

D. increased heart rate

36. Which of the following is a vasoconstrictor that is released when blood pressure falls or sodium concentration in the blood is reduced?

A. ADH

B. renin

C. angiotensin

D. aldosterone

37. On average, what percentage of an individual’s daily water intake comes from beverages?

A. 60 percent

B. 70 percent

C. 80 percent

D. 90 percent

38. Which food has the greatest water content?

A. beef

B. ice cream

C. oatmeal

D. cucumber

39. Which of the following safe metals found in tap water typically adds to its “hardness”?

A. iron

B. lead

C. tungsten

D. magnesium

40. Around ________ of Americans get fluoride in their tap water, which helps reduce the level of dental caries.

A. one-fourth

B. one-third

C. one-half

D. two-thirds