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.

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. 

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.

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 .

58. A difference between a stem and a root in secondary growth is that the root often lacks ______. (A) xylem (B) vascular cambium (C) pith (D) parenchyma rays (E) cork

複選題59. For invertebrates, which statement is NOT CORRECT?(A) Molluscs are the most diverse phylum.(B) Trematodes have very sophisticated defenses against immune system attack.(C) Tapeworms lack a mouth and a gut.(D) Echinoderms and vertebrates are more closely related than arthropods.(E) Barnacles are classified as mollusks because of their trochophore larvae.

複選題60. Which statement is true for seed plants? (A) In angiosperm life cycles, the female gametophyte is the ovule. (B) A spore grows into a seed. (C) A pollen grain contains a male gametophyte. (D) Double fertilization results in the production of a diploid zygote and a triploid endosperm nucleus. (E) The life cycle of seed plants does not include a gametophyte generation. .

61. Which statement is true? (A) Plants are defined as multicellular, eukaryotic, photosynthetic autotrophs. (B) Plants are defined by their chloroplasts, which contain chlorophyll a and b. (C) Plant sporophytes grow from haploid spores. (D) Charophytes and land plants share four derived traits that suggest they share a relatively recent common ancestor. (E) Charophytes are embryophytes.