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.
- 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.
- B.C.D가 아니라는 것을 알고 A를 골랐는데 답의 근거를 찾는것좀 도와주시면 감사하겠습니다. 사실 지문에서 말하는 공기의 흐름 메카니즘이 잘 이해가 가지 않습니다