43.The word “scarce” in line 4 is closest in meaning to
(A) ancient
(B) tiny
(C) available
(D) rare

39.The phrase “affectional tie” in line 29 is closest in meaning to (A) cognitive development (B) emotional attachment (C) psychological need (D) behavioral change

40. It can be inferred from the passage that ethological theory assumes that (A) to learn about human behavior only human subjects should be studied (B) failure to imprint has no influence on inteligence (C) the notion of critical periods applies only to animals (D) there are similarities between animal and human behavior

41.Which of the following does the passage mainly discuss? (A) How patterns in rock layers have been used to construct theories about the climate of the Proterozoic age (B) What some rare fossils indicate about glacial conditions during the late Proterozoic age (C) The varying characteristics of Proterozoic glacial varves in different parts of the world (D) The number of glacial episodes that the Earth has experienced since the Proterozoic age

42. According to the passage, the fossil record of the Proterozoic con is (A) highly regarded because it preserves the remains of many kinds of organisms (B) less informative than the fossil record of more recent periods (C) very difficult to interpret due to damage from bacteria (D) more useful to researchers than other aspects of the rock record

44. It can be inferred from the passage that the principle of uniformitarianism indicates that (A) similar conditions produce similar rock formations (B) rock layers in a given region remain undisturbed over time (C) different kinds of sedimentary rocks may (D) each continent has its own distinctive pattern of sediment layers

45. The word “resemble” in line 14 is closest in meaning to (A) result from (B) penetrate (C) look like (D) replace have similar origins

46. According to the passage, the layers in varves are primarily formed by (A) fossilized bacteria (B) pieces of ancient dropstones (C) a combination of ancient and recent sediments (D) annual cycles of sediment transport and deposition

47. The phrase “the other” in line 17 refers to another (A) annual cycle (B) glacial lake (C) layer of sediment (D) season

48. According to the passage, the presence of dropstones indicates that (A) the glacial environment has been unusually server (B) the fine-grained sediment has built up very slowly (C) there has been a global ice age (D) coarse rock material has been carried great distances

49. Why does the author mention Canada, North America, Africa, India, and Europe in lines 23-24? (A) To demonstrate the global spread of dropstones (B) To explain the principles of varve formation (C) To provide evidence for the theory that there was a global ice age in the early Proterozoic eon (D) To illustrate the varied climatic changes of the Proterozoic con in different parts of the globe