Why does hair turn gray or white as people age?
A. Melanocytes die out.
B. Mitosis slows down in the hair shaft.
C. The shaft becomes rounder in cross-section.
D. Keratin production decreases.
E. Blood supply to the scalp diminishes.
A. Melanocytes die out.
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The primary function of cellular respiration is to ________.
A) determine the amount of heat needed by the human body B) provide the body with adequate amounts of vitamins and minerals C) efficiently monitor the energy needs of the body D) break down food molecules and generate ATP
Which of the following is an example of drug compounding?
a. splitting a pill along its score line b. dispensing an unopened bottle of pills to a client c. using expired drugs to treat an animal's illness d. adding flavoring to formulated drugs
Gas exchange at the respiratory membrane is efficient because
A. the difference in partial pressures is substantial. B. the distances involved in exchange are small. C. the total surface area of the membrane is large. D. blood flow and air flow are coordinated (blood flow is highest around alveoli with highest Po2). E. All of these are correct.
As an arterial pathway moves farther from the heart, the arteries
A. get larger. B. get smaller. C. show no change in their lumen size.