68. Where can the following sentence be inserted into the passage? It’s possible that factors other than having a dog or cat in the house influenced the study participants’ risk of allergy.
(A) [i]
(B) [ii]
(C) [iii]
(D) [iv]

64. What is the main theme of this passage? (A) Keeping pets at home is a way to cure children’s allergies. (B) Pets could be the main source of household allergens. (C) Living with pets may protect young children from allergies. (D) Parents should get rid of pets to prevent children’s allergies.

65. Why is the research important? (A) It conducts longitudinal follow-ups on children until they were 18. (B) It identifies pet-related bacteria from household pets that cause asthma. (C) It confirms that exposures to pets strengthen children’s immune system. (D) It concludes that dust, not pets, provokes allergies in the infancy.

66. Which of the following argument is suggested in the research? (A) Teenagers owning cats or dogs are less likely to develop allergies to those animals later in life. (B) A child who has been living with pets anytime after one year old has a significant lower risk of having allergies. (C) There is a certain period of time in which exposure to pets may have a protective effect against allergies. (D) Sending away pets is an effective way to prevent children’s allergies.

67. What of the following is closest in meaning to the word “mystified” (in line 7)? (A) upset (B) bewildered (C) satisfied (D) bestowed

69. According to the passage, which of the following factors MOST influences where life is found on Earth? (A) Climatic conditions. (B) The length of days and nights. (C) Ocean tides. (D) Geographic boundaries.

70. According to the passage, plants on the tundra grow close to the ground (A) to avoid being eaten by arctic animals. (B) because fertilizer is not readily available. (C) to minimize exposure to the cold. (D) because unfrozen water supplies are very scarce.

71. According to the passage, which of the following can be found in the greatest number of different climate areas on Earth? (A) Reef corals. (B) Penguins. (C) Bears. (D) Camels.

72. It can be inferred from the passage that foraminifers are a (A) kind of weather pattern. (B) form of sea life. (C) species of tundra plant. (D) type of miniature penguin.

73. According to the passage, human beings can survive almost everywhere on Earth because (A) they have developed advanced forms of transportation. (B) they have learned how to process seawater for drinking. (C) their body temperature can vary considerably. (D) their shelters and clothing help them to adapt to the environment.

74. Which of the following sentence from the passage is the effect, rather than the cause? (A) Languages seem to be converging to a smaller number. (B) Languages like English seem to eat up regional ones. (C) The three languages used the most by first language speakers today are Mandarin Chinese, English, and Spanish. (D) The estimated rate of language extinction is one lost in the world every two weeks.