38. The word "others" in line 21 refers to
(A) private messages
(B) species
(C) trails
(D) signals

34.According to the passage, each nest has a distinct odor that allows its inhabitants to (A) find the location of the nest in the dark (B) distinguish worker ants from other ants (C) distinguish foreign ants from resident ants (D) signal other inhabitants when foreign ants attack

35. The word "alert" in line 13 is closest in meaning to (A) allow (B) transport (C) ware (D) provide

36. What is the role of pheromones in the mass migrations of ants? (A) Pheromones are used to create a trail that directs the ants during migrations. (B) Pheromones signal the ants that the nest has been invaded and must be abandoned. (C) Pheromones control the speed at which ants move from one location to another. (D) Pheromones enable scouts to identify suitable areas for establishing a new nest.

37. The word "scurrying" in line 16 is closest in meaning to (A) agreeing (B) appearing (C) competing (D) rushing

39. Why does the author mention "dead insects" in line 23 ? (A) To compare the social behaviors of ants with those of other insects (B) To emphasize the dangers that all insects encounter (C) To argue the superiority of ants over other insects (D) To indicate a behavior that is common among various kinds of ants

40. Which of the following terms is defined in the passage? (A) pheromones (line 2) (B) colony integrity (lines 11-12) (C) mass migrations (line 14) (D) private messages (lines 18-19)

41. Which aspect of the Homestead Act of 1862 does the passage mainly discuss? (A) How it transformed the western United States into a place of small farms (B) Why it was an improvement over previous attempts at land reform (C) Why it did not achieve its aim to provide land for small farmers (D) How it failed in the largely treeless states of Kansas, Nebraska, and the Dakotas

42. An amendment added to the Homestead Act of 1862 specified that (A) five years of residence was required for landownership (B) husbands and wives could not file separate claims (C) the price of 160 acres of land was $1,000 (D) land could not be resold for a profit

43. The word "formidable" in line 12 is closest in meaning to (A) obvious (B) predictable (C) difficult (D) manageable

44. It can be inferred that the "safety valve" in line 13 refers to (A) a new kind of machinery (B) an alternative for urban workers (C) an area in a factory (D) a procedure designed to protect workers