51. An open circulatory system differs from a closed one in that:
(A) The open circulatory system has a combination of blood vessels and large thin-walled sinuses whereas a closed circulatory system has only vessels.
(B) An open circulatory system opens into the heart whereas the closed circulatory system does not.
(C) An open circulatory system opens into arteries and is drained by veins whereas in a closed one it is just the reverse.
(D) An open circulatory system drains into the mantle cavity whereas a closed circulatory system drains into the hemolymph.
(E) A closed circulatory system is completely encased in the body cavity whereas the open one is not. 

47. The driving force that pushes the root tip through the soil is primarily ______. (A) the elongation of root hairs (B) continuous cell division of root cap cells (C) elongation of cells behind the root apical meristem (D) continuous cell division in the root cap at the tip of the root (E) continuous cell division just behind the root cap in the center of the apical meristem

48. Iron deficiency is often indicated by yellowing in newly formed leaves. This suggests that iron ______. (A) is a relatively immobile nutrient in plants (B) is concentrated in the xylem of older leaves (C) is tied up in formed chlorophyll molecules (D) is concentrated in the phloem of older leaves (E) is found in leghemoglobin and reduces the amount available to new plant parts

49. You find a new species of mouse that, compared to the house mouse you are familiar with, sprints extraordinarily rapidly but also fatigues quickly. Which type of muscle fiber (compared to an ordinary house mouse) would you expect to see an increase in ______? (A) slow glycolytic fibers (B) slow oxidative fibers (C) fast glycolytic fibers (D) fast oxidative fibers (E) fast and slow oxidative fibers

50. Which of the following is true about short-term and long-term memory processes? (A) Both short-term and long-term memory processes require protein synthesis. (B) Neither short-term nor long-term memory processes require protein synthesis. (C) Invertebrate animals like Aplysia and Drosophila do not show long-term memory processes. (D) Short-term memory processes act through second messenger systems while long-term memory processes require protein synthesis. (E) Long-term memory processes act through second messenger systems while short-term memory processes require protein synthesis. .

52. In the above graph, curve ______ is most likely the oxygen-binding curve for normal adult human hemoglobin. Curve ______ is most likely that of llama hemoglobin (from a llama population that has lived in the mountains of Peru for thousands of years). Curve ______ is most likely that of myoglobin. (A) A, B, C (B) A, C, B (C) B, C, A (D) B, A, C (E) C, B, A

53. A small island has stable populations of plants and animals, including one species of hawk as the only predator. A ship docks at the island, and the ship's cat has recently had a litter of kittens. One of the young cats accidentally goes ashore in a small boat, jumps to land and runs into the brush. No one notices, and they leave the cat on the island. What do you think is a likely consequence of the cat's presence on the island? (A) The insect populations will decline. (B) The fish in the lagoon will decrease due to predation. (C) It's only one cat and will make no difference to the island. (D) Some species of ground-nesting birds may go extinct within a few years. (E) The increase in nitrogenous waste from the cat will increase the size of many plants.

54. Which is NOT CORRECT? (A) Introduced species are sometimes a problem because they usually are better competitors. (B) For carbon cycle, the CO2 would be returned to the atmosphere when the trees died and decayed. (C) Global warming is caused by increased CO2 and CH4 levels. (D) UV-B radiation is increasing due to increased CH4 concentration in the polar region. (E) CO2 level increased due to enhanced human activities.

55. Which statement about hyperpolarization of a neuron is true? When hyperpolarization occurs, (A) membrane potential is more negative than during resting potential. (B) membrane potential is closer to Na+ equilibrium potential (ENa) than it is to EK. (C) Na+ and/or Cl− channels are open. (D) if it occurs in a downstream neuron, exciting postsynaptic potentials (EPSPs) are more likely to be generated than are inhibitory PSPs (IPSPs). (E) generation of action potentials is likely to occur.

複選題56. Which of the statement about digestion system in animals is correct? (A) Stomach acid activates pepsinogen into pepsin. (B) Secretin modulates digestion by triggering acid release in the stomach. (C) The bile salts function in fat digestion by dispersing big droplets of fats to small droplets. (D) A fatty acid absorbed into an intestinal cell becomes part of a chylomicron. (E) Glucagon, the pancreatic hormone, functions to stimulate the liver to release glucose. .

【已刪除】57. For the reproduction of flowering plants, double fertilization: (A) is characteristic of all plants. (B) produces a triploid sporophyte and a diploid endosperm. (C) results in the fertilization of egg by sperm and polar nuclei by pollen tube nucleus. (D) results from the fusion of the male and female sporophytes of angiosperms. (E) 送分 .