1. Why must multicellular organisms keep their cells awash in an "internal pond"?
a. Negative feedback will only operate in interstitial fluids.
b. Cells need an aqueous medium for the exchange of nutrients, gases, and wastes.
c. Cells of multicellular organisms tend to lose water because of osmosis.
d. Cells of multicellular organisms tend to accumulate wastes, a consequence of diffusion.
e. This phenomenon occurs only in aquatic organisms because terrestrial organisms have adapted to life in dry environments.

2. In a typical multicellular animal, the circulatory system interacts with various specialized surfaces in order to exchange materials with the exterior environment. Which of the following is not an example of such an exchange surface.
a. lung
b. muscle
c. skin
d. intestine
e. kidney

3. Which of the following is an example of positive feedback?
a. An increase in blood sugar concentration increases the amount of the hormone that sotres sugar as glycogen.
b. A decrease in blood sugar concentration increases the amount of the hormone that converts glycogen to glucose.
c. An infant's suckling at the mother's breast increases the amount of the hormone that induces the release of milk from the mammary glands.
d. An increase in calcium concentration increases the amount of the hormone that stores calcium in bone.
e. A decrease in calcium concentration increases the amount of the hormone that releases calcium from bone.

4. Consider an ecototherm and an endotherm of equal body size. The ecototherm is more lifely to survive an extended period of food deprivation than the endotherm because
a. the ectotherm is sustained by a higher basal metabolic rate.
b. the ecototherm will expend less energy/kg body weight than the endotherm.
c. the ectotherm will invest little to no energy in temperature regulation
d. actually, assuming equal size, the ectotherm and the endotherm will have the same energy expenditures.
e. both B and C

5. Terrestrial animals mainly exchange heat with the environment by all of the following physical processes except
a. conduction.
b. convection.
c. evaporation.
d. illumination.
e. radiation.

6. All of the following are mechanisms of thermoregulation in terrestrial mammals except
a. changing the rate of evaporative heat loss.
b, changing the rate of metabolic heat production.
c. changing the rate of heat exchange by conforming to environmental temperatures.
d. changing the rate of heat loss by vasodilation and vasoconstruction.
e. relocating to cool areas when too hot, or to warm areas when too cold.

Use this figure to answer questions 8 & 9.


7. What does the difference in temperature between arteries and veins in the goose's legs indicate?
a. The legs need to be kept cool so that muscles will function well.
b. The feet need to be kept very warm so they do not freeze in water.
c. Heat loss is proportional to the difference in temperature inside and outside, so minimizing the difference means the goose will lose less heat.
d. Arterial blood helps return heat to the core of the goose.
e. Warm venous blood is necessary to keep the goose's feet from freezing.

8. The temperature difference between arterial blood and venous blood near the goose's body
a. is minimized by countercurrent exchange.
b. is maximized because the blood has run through very cold feet.
c. is minimized by dilation of the capillaries in the feet of the goose, allowing heat to be lost.
d. is more than the difference between the venous blood near the body and the venous blood at the feet.
e. allows the goose to lose maximum heat to the environment.

9. You are studying a large tropical reptile that has a high and relatifvely stable body temperature. How would you determine whether this animals is an endotherm or an ecototherm?
a. You know from its high and stable body temperature that is must be an endotherm.
b. You know that it is an ectotherm because it is not a bird or mammal.
c. You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
d. You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
e. You measure the metabolic rate of the reptile and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

10. Compared to a smaller cell, a larger cell of the same shape has
a. less surface area.
b. less surface area per unit of volume.
c. the same surface-to-volume ratio,
d, a smaller average distance between its mitochondria and the external source of oxygen.
e. a smaller cytoplasm-to-nucleus ratio.