49. What is the single greatest threat to biodiversity throughout the biosphere?
(A) overharvesting of commercially important species
(B) introduced species that compete with native species
(C) pollution of Earth's air, water, and soil
(D) disruption of trophic relationships as more and more prey species become extinct
(E) habitat alteration, fragmentation, and destruction

45. Which of the following is NOT a function of rhizobacteria? (A) produce hormones that stimulate plant growth (B) produce antibiotics that protect roots from disease (C) absorb toxic metals (D) carry out nitrogen fixation (E) supply growing roots with glucose

46. Epiphytes are ______ (A) fungi that attack plants. (B) plants that have a symbiotic relationship with fungi. (C) nonphotosynthetic parasitic plants. (D) plants that live in poor soil and digest insects to obtain nitrogen. (E) plants that grow on other plants but do not obtain nutrients from their hosts.

47. What do Wernicke's and Broca's regions of the brain affect? (A) olfaction (B) vision (C) speech (D) memory (E) hearing

48. According to Hamilton's rule, (A) natural selection does not favor altruistic behavior that causes the death of the altruist. (B) natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist. (C) natural selection is more likely to favor altruistic behavior that benefits an offspring than altruistic behavior that benefits a sibling. (D) the effects of kin selection are larger than the effects of direct natural selection on individuals. (E) altruism is always reciprocal.

50. All of the followings belong to the Eumetazoa, EXCEPT(A) Porifera(B) Platyhelminthes(C) Mollusca(D) Annelida(E) Nematoda Ⅱ.

51. About hormonal circuits that link kidney function, which of the following statements is INCORRECT? (A) An increase in blood osmolarity triggers the release of antidiuretic hormone (ADH), which helps to conserve water. (B) ADH increases water reabsorption in the descending limb of the Loops of Henle. (C) The Renin-Angiotensin-Aldosterone System (RAAS) is part of a complex feedback circuit that functions in the maintenance of blood pressure and volume. (D) A drop in blood pressure near the glomerulus causes the juxtaglomerular apparatus (JGA) to release the enzyme renin. (E) Renin triggers the formation of the peptide angiotensin II, which increases blood volume and pressure by stimulating the release of aldosterone.

52. About respiratory pigment, which of the following statements is INCORRECT? (A) Respiratory pigments are proteins that transport oxygen and greatly increase the amount of oxygen that blood can carry. (B) Arthropods and many molluscs have hemocyanin with copper as the oxygen-binding component. (C) Hemoglobin is involved in the transport of O2 but not CO2. (D) A small change in the partial pressure of oxygen can result in a large change in delivery of O2. (E) CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2; this is called the Bohr shift.

53. Which of the followings would a paleontologist be most likely to do in order to determine whether a fossil represents a reptile or a mammal? (A) Look for the mammalian characteristics of a four-chambered heart and a diaphragm. (B) Because mammals are eutherians, look for evidence of a placenta. (C) Use molecular analysis to look for the protein keratin. (D) Examine the teeth. (E) Look for the presence of milk-producing glands.

54. Which of the following statements about connective tissue is INCORRECT? (A) Loose connective tissue binds to epithelial to underlying tissues and holds organ in place. (B) Fibrous connective tissue is found in tendons and ligaments. (C) Three types of connective tissue fibers are collagenous fibers, reticular fibers and elastic fibers. (D) Both cartilage and bones are connective tissues, but blood composed of blood cells and cell fragments in blood plasma is not. (E) Fibroblasts that secret proteins of extracellular matrix are one major cell type in connective tissue.

55. About human disorders due to chromosomal alterations, which of the following statements is INCORRECT? (A) Down’s syndrome is an aneuploid condition that results from three copies of chromosome 21. (B) Turner syndrome is the only known viable monosomy X in female human. (C) Klinefelter syndrome is the result of an extra chromosome in a male producing XXY individuals. (D) Certain cancers, including chronic myelogenous leukemia are caused by chromosome translocation. (E) cri du chat (“cry of the cat”) syndrome results from a specific duplication of chromosome 5.