42. The purpose of the second mention of "hormones" in line 4 is to point out
(A) chemical signals that are common among insects
(B) specific responses of various species to chemical signals
(C) similarities between two chemical substances
(D) how insects produce different chemical substances

38. According to the passage, which of the following changes occurred in English gardens during the European settlement of North America? (A) They grew in size in order to provide enough plants to export to the New World. (B) They contained a wider variety of tulips than ever before. (C) They contained many new types of North American plants. (D) They decreased in size on the estates of wealthy people.

39. The passage mentions which of the following as a problem associated with the importation of tulips into North America? (A) They were no longer fashionable by the time they arrived. (B) They often failed to survive the journey. (C) Orders often took six months or longer to fill. (D) Settlers knew little about how to cultivate them.

40. What does the passage mainly discuss? (A) How insects use pheromones to communicate (B) How pheromones are produced by insects (C) Why analyzing insect pheromones is difficult (D) The different uses of pheromones among various insect species

41. The word "serve" in line I is closest in meaning to (A) improve (B) function (C) begin (D) rely

43. The word "sole" in line 6 is closest in meaning to (A) obvious (B) best (C) only (D) final

44. The passage suggests that the speed at which communication through pheromones occurs is dependent on how quickly they (A) lose their effectiveness (B) evaporate in the air (C) travel through the air (D) are produced by the body

45. According to the passage, the meaning of a message communicated through a pheromone may vary when the (A) chemical structure of the pheromone is changed (B) pheromone is excreted while other pheromones are also being excreted (C) exocrine glands do not produce the pheromone (D) pheromone is released near certain specific organisms

46. The word "detecting" in line 23 is closest in meaning to (A) controlling (B) storing (C) questioning (D) finding

47. According to paragraph 2, which of the following has made the study of pheromones difficult? (A) Pheromones cannot be easily reproduced in chemical laboratories. (B) Existing technology cannot fully explore the properties of pheromones. (C) Pheromones are highly volatile. (D) Pheromone signals are constantly changing.

48. The word "They" in line 24 refers to (A) pheromones (B) roles (C) activities (D) insects