托福阅读常考话题及练习题推荐四：动物行为变化（3）

1托福阅读常考话题：动物行为变化练习题

Paragraph 5: But how is this well-insulated nest ventilated? Its many occupants require over 250 quarts of oxygen (more than 1,200 quarts of air) per day. How can so much oxygen diffuse through the thick walls of the mound? Even the pores in the wall are filled with water, which almost stops the diffusion of gases. The answer lies in the construction of the nest. The interior consists of a large central core in which the fungus is grown, below it is “cellar” of empty space, above it is an “attic” of empty space, and within the ridges on the outer wall of the nest, there are many small tunnels that connect the cellar and the attic. The warm air in the fungus gardens rises through the nest up to the attic. From the attic, the air passes into the tunnels in the ridges and flows back down to the cellar. Gases, mainly oxygen coming in and carbon dioxide going out, easily diffuse into or out of the ridges, since their walls are thin and their surface area is large because they protrude far out from the wall of the mound. Thus air that flows down into the cellar through the ridges is relatively rich in oxygen, and has lost much of its carbon dioxide. It supplies the nest’s inhabitants with fresh oxygen as it rises through the fungus-growing area back up to the attic.

10.According to paragraph 5, what does the thinness of the ridge walls make possible?

A. The concentration of cool air in the cellar

B. The construction of exceptionally long tunnels

C. The even distribution of oxygen from attic to cellar

D. The diffusion of gases into and out of the ridges

11.According to paragraph 5, what happens to the air in the ridge tunnels of Macrotermes natalensis nests?

A. It becomes more humid as water vapor diffuses into the tunnels.

B. It loses carbon dioxide and gains oxygen.

C. It reaches the interior of the nest through pores in the walls.

D. It moves in the same direction as the air in the center of the nest.

12.Paragraph 5 supports which of the following about the air that flows through the interior of a Macrotermes natalensis mound?

A. It has a higher concentration of oxygen in the cellar than in the attic.

B. It is the same temperature as the air on the outside of the mound.

C. It contains over 250 quarts of oxygen which circulate continuously.

D. It is most humid in the cellar and gradually loses moisture as it rises to the attic.

Paragraph 5: But how is this well-insulated nest ventilated? Its many occupants require over 250 quarts of oxygen (more than 1,200 quarts of air) per day. How can so much oxygen diffuse through the thick walls of the mound? [■] Even the pores in the wall are filled with water, which almost stops the diffusion of gases. [■] The answer lies in the construction of the nest. [■] The interior consists of a large central core in which the fungus is grown, below it is “cellar” of empty space, above it is an “attic” of empty space, and within the ridges on the outer wall of the nest, there are many small tunnels that connect the cellar and the attic. [■] The warm air in the fungus gardens rises through the nest up to the attic. From the attic, the air passes into the tunnels in the ridges and flows back down to the cellar. Gases, mainly oxygen coming in and carbon dioxide going out, easily diffuse into or out of the ridges, since their walls are thin and their surface area is large because they protrude far out from the wall of the mound. Thus air that flows down into the cellar through the ridges is relatively rich in oxygen, and has lost much of its carbon dioxide. It supplies the nest’s inhabitants with fresh oxygen as it rises through the fungus-growing area back up to the attic.

13.Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

If not through the walls or its pores, how does oxygen enter the nest at all, since the nest has a closed surface?

14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 3 points. Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it. Termites are social insects that live in large, often elaborately constructed nests.

A. Although termites resemble ants in terms of size, metamorphosis, and social organization, they actually belong to a different order of insects.

B. Some termites build their nests underground, while other construct above-ground structures with thick, insulating wall.

C. Some termite species grow a fungus in their nests so that it will purify the air by taking in carbon dioxide and giving off oxygen.

D. Termites are sensitive to dryness and to changes in temperature, so their nests are designed to minimize these factors.

E. Whether they lie above ground or below ground, termite nests must include special pores that allow air to enter the nests.

F. The nests of Macrotermes natalensis consist of a series of chambers and tunnels that allow for the circulation of air and the exchange of oxygen and carbon dioxide.