Fishes, like other animals,take in oxygen to burn their food during respiration,and they produce carbon dioxide (CO2)as a waste product.▉Early bony fishes living in the sea may have developed the ability to breathe air because the process of respiration in air has many advantages over that of respiration in water.▉It is easier and more efficient to extract oxygen from air rather than water.▉Water is hundreds of times denser than air,and even at best it contains less oxygen. Many all-breathing animals have to pump external water across their gill surfaces at ten times the rate they pump their internal blood.▉Gills have to be designed to resist the leakage of dissolved body salts,and the tissues across which oxygen is exchanged cannot be as thin as they can in air, so gas exchange is rarely anywhere near 100 percent efficient.
1.According to paragraph 1,which of the following is NOT one of the reasons why it is easier and more efficient to extract oxygen from air than from water?
A.To receive the same amount of oxygen, gill-breathing animals must pump ten times more blood than air-breathing animals do.
B.Gas exchange in water is not as efficient as in air because gills need to hold body salts.
C.Water is much denser than air.
D.Water contains less oxygen than air.
Because oxygen diffuses 10000 times more quickly in air than in water,oxygen-poor air is rare. But oxygen-poor water does occur quite often, especially in tropical regions, wherever warm freshwater or saltwater lakes,ponds, or lagoons are partly or completely isolated, especially in hot seasons. Warm, rotting debris can quickly use up oxygen,specially if there is little or no natural water flow Even if the effect is only seasonal, it may still be crucial for fishes and other organisms living in the water. The water is stagnant, hot, and full of rotting debris, often teeming with bacteria that may also release toxic substances.
2.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
A.But tropical lakes, ponds, and lagoons often become partly or completely isolated during hot seasons,
B.But oxygen-poor water is common, especially where the water is isolated and the conditions are warm.sh
C.Oxygen- poor water in tropical regions is often found in places where freshwater and saltwater mix
D.Oxygen-poor water might sometimes occur, but only in tropical regions during their hot seasons.
3.According to paragraph 2, which of the following is a major reason for the poor oxygen supply in some bodies of water?
A.The inflow of warmer water from nearby bodies of water
B.The breakdown of materials in isolated bodies of water
C.Seasonal changes in the number of fishes and other organisms living in the water
D.Diffusion of oxygen into the air
Why do some fishes live in oxygen-poor water, where gill breathing is difficult? The food supply may be rich for fishes that can tolerate it, and there are situations in which fishes might benefit from swimming into areas of warm, often oxygen-poor water near the surface. Many carnivorous fishes today are bottom-feeders, hunting for small prey that live on or in the surface of the sediment (a loose layer of material at the bottom of a body of water). In warm latitudes, the bottom waters are often much cooler than the surface waters,which are heated by the sun.Digestion can be very slow in cold-blooded animals such as fishes, especially if they live in cold environments. It may be the critical factor holding back growth and development. In such cases, increasing the digestive rate by swimming into the warm surface water can produce faster growth, earlier maturity, and more successful reproduction. But what happens to a fish that swims into surface water because it is warm,only to find that it is also oxygen poor? Even if surface waters are generally low in oxygen, there is always a thin surface layer of water, about a millimeter thick,that absorbs oxygen from the air by diffusion.
4.The word “tolerate” in the passage is closest in meaning to
A.endure
B.make use of
C.find
D.solve
5.In paragraph 3,why does the author provide information about the effects of cold temperatures on the digestion of cold-blooded animals?
A.To emphasize how attractive the food supply in bottom waters is for some fishes
B.To provide an example of another disadvantage that is faced by fishes that live in oxygen-poor water where gill breathing is difficult
C.To support the claim that there are situations in which fishes benefit from swimming into oxygen-poor surface water
D.To explain why fishes that live near the bottom in warm latitudes tend to be carnivorous
Many fishes in tropical environments come to this surface layer to bathe their gills in the surface oxygen layer. They can breathe,but they have other problems to solve. For example, if they break the surface,their bodies may extend out into the air,losing some buoyancy (ability to float).
Some fishes in this situation bite off bubbles of air,hold them in their mouths to stay afloat, and remain at the surface without active swimming. Some species of gobies breathe this way. Once they have an air bubble,they can extract oxygen from it in the back of their mouths much more efficiently than through the gills. When the oxygen level in the mouth bubble falls,reducing its size and its buoyancy, the fish must then get rid of the bubble and bite off another. Rhythmic air breathing might have evolved as a result of this action,as fishes began to get rid of CO2 from their mouth bubbles while losing it at gill surfaces as well.
6.According to paragraph 5,a fish releases a bubble that it has bitten off when
A.the fish stops swimming actively
B.the oxygen in the bubble decreases
C.the oxygen level in the water rises
D.the gill surfaces begin to lose CO2
7.Paragraph 5 suggests which of the following about bubble breathing?
A.It is less efficient than other methods of acquiring oxygen.
B.It was very rhythmic in the early stages of the evolution of the process.
C.It does not involve gills.
D.It does not result in production of CO2.
Oxygen intake in the mouth enriches the blood supply there,and a fish can store oxygen in an air bubble. An air bubble that takes up only 5 percent of body volume can multiply oxygen storage ten times compared with a fish without a bubble. As a result,a bubble-breathing fish need not stay near the surface. In fact, the fish can make extended dives to the bottom.This is true today of all air breathers with low metabolic rates, including crocodiles and turtles. Many water-dwelling insects and spiders use air bubbles too.
8.According to paragraph 6, air bubbles allow air -breathing fishes, crocodiles, and turtles to do which of the following?
A.Increase the volumes of their bodies by 5 percent
B.Catch water dwelling insects and spiders
C.Stay at the bottom for a long time
D.Compete with other animals that also rely on air bubbles
9.Look at the four squares[ █ ]that indicate where the following sentence can be added to the passage.Where would the sentence best fit?
Most species of fish breathe in water by means of specialized organs,called gills,but this is not true for all species.
10.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the 3 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 2 points.) Drag your choices to the spaces where they belong. To review the passage, click on view text.Some fishes can breathe through means other than gills.
A.Oxygen-poor water can provide fishes with a large food supply ,and when such water is warm, it can also improve the growth and digestion of
B.Even under the best circumstances, water has less oxygen than air, and some fishes have evolved strategies for breathing in oxygen-poor waters.
C.Biting off bubbles of air can help fishes stay at the thin,oxygen- rich surface layer, and it also provides a means of storing oxygen.
D.ills have evolved to release carbon dioxide into the water, which also makes them likely to lose some of the oxygen they take in before it can be used.
E.Breathing through gills has some advantages over bubble breathing, such as more efficient digestion,faster growth,and more successful reproduction.
F.Breathing air from bubbles may have resulted in the evolution of low metabolic rates and contributed to the spread of reptiles such as turtles and crocodiles.
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