28. Polar regions are cooler than the equator because
(A) the poles are permanently tilted away from the sun.
(B) there is more ice at the poles.
(C) the poles have a thicker atmosphere.
(D) sunlight strikes the poles at an oblique angle.
(E) the poles are farther from the sun.

24. The postsynaptic membrane of a nerve may be stimulated by certain neurotransmitters to permit the influx of negative chloride ions into the cell. This process will result in (A) the membrane becoming more positive. (B) membrane depolarization. (C) the production of an EPSP. (D) the production of an IPSP. (E) an action potential.

25. The pathway leading to the perception of sound begins with the (A) hair cells of the organ of Corti, which rests on the tectorial membrane, coming in contact with the basilar membrane. (B) hair cells of the organ of Corti, which rests on the tympanic membrane, coming in contact with the tectorial membrane. (C) hair cells of the organ of Corti, which rests on the basilar membrane, coming in contact with the tectorial membrane. (D) hair cells on the tympanic membrane that stimulate the tectorial membrane neurons leading to the auditory section of the brain. (E) hair cells of the organ of Corti coming in contact with the tectorial membrane as a result of fluid waves in the cochlea causing vibrations in the round window.

26. What is the structure diagrammed in Figure 1? (A) an ommatidium (B) a neuromast (C) a statocyst (D) a taste bud (E) an olfactory bulb

27. Coral reefs can be found on the southern east coast of the United States but not at similar latitudes on the southern west coast. Differences in which of the following most likely account for this? (A) ocean currents (B) precipitation (C) sunlight (D) day length (E) salinity

29. Reconciliation behavior is likely to follow (A) imprinting by young animals on a member of the wrong species. (B) conflict behavior between members of a permanent social group. (C) mating behavior between a male and a female. (D) agonistic behavior between territorial males. (E) ritualized behavior.

30. In the 14th century, _____ was responsible for the death of more than one-third of the entire European population of humans. (A) pneumonia (B) bubonic plague (C) AIDS (D) influenza (E) tuberculosis

31. Population ecologists follow the fate of same-age cohorts in order to (A) determine the factors that regulate the size of a population. (B) determine a population's carrying capacity. (C) determine if a population is regulated by density-dependent processes. (D) determine the birth rate and death rate of each age group in a population. (E) determine if a population's growth is cyclical.

32. The growing season would generally be shortest in which of the following biomes? (A) taiga (B) temperate broadleaf forest (C) savanna (D) tropical rain forest (E) temperate grassland

33. Which marine zone would have the lowest rates of primary productivity (photosynthesis)? (A) abyssal (B) intertidal (C) neritic (D) continental shelf (E) pelagic

34. In the territorial behavior of the stickleback fish, the red belly of one male elicits attack from another male by functioning as (A) a pheromone. (B) a sign stimulus. (C) an imprint stimulus. (D) a fixed action pattern. (E) a search image.