41. Which of the following best illustrates homeostasis?
(a) All the cells in the body have much the same chemical composition.
(b) Cells of the skin are constantly worn off and replaced.
(c) When blood CO2 increases, you breathe faster and get rid of CO2.
(d) All organs are composed of the same four kinds of tissues.
42. How does a gastrovascular cavity differ from an alimentary canal? The gastrovascular cavity
(a) stores food but does not digest it.
(b) absorbs food molecules but does not produce hydrolytic enzymes.
(c) has only a single opening.
(d) functions in digestion but not absorption.
43. In humans, most nutrient molecules are absorbed by the
(a) stomach. (b) liver.
(c) small intestine. (d) large intestine.
44. The largest variety of digestive enzymes function in the
(a) large intestine. (b) oral cavity.
(c) stomach. (d) small intestine.
45. Which of the following is not an essential nutrient for a human?
(a) linoleic acid, a fatty acid (b) glucose, a monosaccharide
(c) methionine, an amino acid (d) ascorbic acid, a vitamin
46. Individuals lacking adequate levels of enterogastrone would have the greatest difficulty digesting
(a) fats. (b) proteins.
(c) carbohydrate (d) nucleic acids.
47. It is important to get some vitamin B-1 every day, but it is all right if intake of vitamin A varies a bit. Why?
(a) Vitamin B-1 is an essential nutrient, and vitamin A is not.
(b) Vitamin A can be stored by the body, but vitamin B-1 cannot.
(c) The body needs much larger amounts of vitamin B-1 than vitamin A.
(d) The body requires vitamin B-1, but vitamin A is just an “extra.”
48. How would you expect the digestive system of a hawk, a carnivore, to compare with that of a sparrow, a seed-eater?
(a) The hawk would have a larger gastrovascular cavity.
(b) The sparrow’s digestive system would be longer.
(c) The hawk would have a gizzard, but the sparrow would not.
(d) The hawk digestive system would be longer.
49. Gallstone surgery sometimes requires that the gallbladder be remove. Patients are then advised to avoid ingesting large amount of fat because
(a) the gallbladder makes bile, which is necessary for fat emulsification.
(b) without the bile produced by the gallbladder, fats cannot be enzymatically hydrolyzed.
(c) the gallbladder produces the hormone enterogastrone.
(d) the gallbladder stores large quantities of bile, releasing it when necessary.
50. Researchers provided radioactively labeled food to a dog, and traced the movement of absorbed molecules. Which type of molecule would move along a different path than all the others?
(a) carbohydrates (b) proteins
(c) nucleic acids (d) fats
