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

30. What aspect of ants does the passage mainly discuss? (A) The relationship between the queen and the worker ants (B) Ways in which ants use chemical signals (C) Methods ants use to identify food sources (D) The importance of respiration in the production of ant pheromones

31. The phrase "smooth operation" in line 1 is closest in meaning to (A) daily activity (B) effective functioning (C) delicate balance (D) permanent location

32. According to the passage, carbon dioxide serves which of the following functions for fire ants? (A) It protects the queen. (B) It attracts other ant species. (C) It informs workers of possible danger. (D) It encourages the ants to gather together.

33. The word "cluster" in line 4 is closest in meaning to (A) organ (B) activity (C) group (D) cycle

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

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

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)