The physical and chemical properties of water, unsurprisingly, determine much about life in the ocean. Water is dense (high mass per unit of volume), about 840 times as dense as air—roughly as dense as most life forms, as they are primarily made of water. This means that marine organisms fight no battle with gravity and possess none of the structures that we need on land to combat it. In the ocean, there are no tree trunks. The closest analogy would be the stipes (stalks) of the large seaweeds known as kelp, allowing kelp to form “forests.” But these stipes do not hold the kelp up—they just hold it in place. At low tide the kelp collapses. Likewise, marine animals can have flexible skeletons or no skeleton at all. This makes it much easier to become large. The major problem with the density of the ocean comes in the depths, where the weight of all that seawater bears down, creating enormous pressures.
Related to density is viscosity—or, basically, thickness due to internal friction. It is about sixty times easier to move through air than water. The importance of this friction depends on how big one is and how fast one is moving. It is much more significant for the little creatures. As a result, while a killer whale can cruise at about ten kilometers per hour, krill, weighing about 0.2 grams, can achieve only about 0.2 kilometers per hour. So, in the viscous ocean the little animals move slowly, giving the big ones a significant advantage. There are no darting ocean insects. Some medium-sized animals, like flying fish and leaping dolphins, leave the water when they want to move really fast.
Water dissolves other substances better than any other common liquid. This allows it to function as the medium for chemical communication using hormones within animal bodies. Seawater includes all kinds of dissolved substances, including, of course, salt. Many of these substances are important for marine life, but none has the significance of oxygen, which all animals need to power their bodies. Seawater is about 0.5–0.9 percent oxygen at the surface. Most marine animals use gills to get oxygen from seawater into their bodies. A few, including the marine mammals, come to the surface and breathe the air. Coming to the surface may have costs in time, energy, or vulnerability to predators, but it has benefits, too, primarily that air is 21 percent oxygen.
Few animals just sit, or move aimlessly along, waiting for good things, like food or mates, or dangerous things, like predators, to come their way. They sense their environment and change their physiology or behavior, and they communicate with each other. One can sense and communicate through a variety of channels, primarily what we call the five senses: touch, taste, smell, hearing, and sight. Moving from the air to water changes the relative benefit of each of the senses. Chemical signals are not dispersed as widely or as predictably under water as in air, so taste and smell have less value for marine animals. Some penguins seem to be able to smell areas with high concentrations of organisms and swim toward them over large ranges, but, tellingly, they do so by smelling the air that they breathe, not by tasting the water that they swim through, even though the organisms they are aiming for are in the water. Sight is also degraded in the ocean because light is absorbed by water. At depths of a few hundred meters there is virtually no light, even in the middle of the day, and even just beneath the surface one can rarely see more than about twenty meters, less than the length of a blue whale.
One sense that does do better underwater is sound. Sound travels about four times faster than in air. More important, and in contrast to light, sound is less weakened by water than air. While there are a few sounds of terrestrial mammals that travel over kilometers— the roars of lions, the rumbles of elephants, and the howls of wolves—most sounds of most terrestrial mammals are lost at much shorter ranges. Many underwater sounds of marine mammals, on the other hand, can be heard in quiet conditions at a kilometer and some travel very much farther.
1
The physical and chemical properties of water, unsurprisingly, determine much about life in the ocean. Water is dense (high mass per unit of volume), about 840 times as dense as air—roughly as dense as most life forms, as they are primarily made of water. This means that marine organisms fight no battle with gravity and possess none of the structures that we need on land to combat it. In the ocean, there are no tree trunks. The closest analogy would be the stipes (stalks) of the large seaweeds known as kelp, allowing kelp to form “forests.” But these stipes do not hold the kelp up—they just hold it in place. At low tide the kelp collapses. Likewise, marine animals can have flexible skeletons or no skeleton at all. This makes it much easier to become large. The major problem with the density of the ocean comes in the depths, where the weight of all that seawater bears down, creating enormous pressures.
In paragraph 1, why does the author mention that kelp collapses at low tide?
ATo illustrate the idea that organisms in the sea lack structures that overcome gravity
BTo provide evidence that kelp is primarily made of water
CTo explain why kelp needs stipes to hold it in place
DTo demonstrate how the enormous pressures in the deep ocean are a major problem
2
The physical and chemical properties of water, unsurprisingly, determine much about life in the ocean. Water is dense (high mass per unit of volume), about 840 times as dense as air—roughly as dense as most life forms, as they are primarily made of water. This means that marine organisms fight no battle with gravity and possess none of the structures that we need on land to combat it. In the ocean, there are no tree trunks. The closest analogy would be the stipes (stalks) of the large seaweeds known as kelp, allowing kelp to form “forests.” But these stipes do not hold the kelp up—they just hold it in place. At low tide the kelp collapses. Likewise, marine animals can have flexible skeletons or no skeleton at all. This makes it much easier to become large. The major problem with the density of the ocean comes in the depths, where the weight of all that seawater bears down, creating enormous pressures.
According to paragraph 1, which of the following is a reason that ocean animals can grow very large?
AThe number of life-forms in the ocean creates enormous pressure for animals to grow larger.
BLarge ocean animals do not need rigid skeletons.
CKelp forests provide a flexible habitat for large animals.
DThere is a lot of room in the deep ocean for large animals.
3
Related to density is viscosity—or, basically, thickness due to internal friction. It is about sixty times easier to move through air than water. The importance of this friction depends on how big one is and how fast one is moving. It is much more significant for the little creatures. As a result, while a killer whale can cruise at about ten kilometers per hour, krill, weighing about 0.2 grams, can achieve only about 0.2 kilometers per hour. So, in the viscous ocean the little animals move slowly, giving the big ones a significant advantage. There are no darting ocean insects. Some medium-sized animals, like flying fish and leaping dolphins, leave the water when they want to move really fast.
In paragraph 2, why does the author compare the swimming speeds of killer whales and krill?
ATo provide support for the idea that moving through air is much faster than moving through water
BTo explain why krill are a common food for whales
CTo support the claim that water’s viscosity affects small animals more than large ones
DTo provide evidence that a small size is a big advantage in the ocean
4
Water dissolves other substances better than any other common liquid. This allows it to function as the medium for chemical communication using hormones within animal bodies. Seawater includes all kinds of dissolved substances, including, of course, salt. Many of these substances are important for marine life, but none has the significance of oxygen, which all animals need to power their bodies. Seawater is about 0.5–0.9 percent oxygen at the surface. Most marine animals use gills to get oxygen from seawater into their bodies. A few, including the marine mammals, come to the surface and breathe the air. Coming to the surface may have costs in time, energy, or vulnerability to predators, but it has benefits, too, primarily that air is 21 percent oxygen.
According to paragraph 3, which TWO of the following statements about seawater are true? To receive credit, you must select TWO answer choices.
AThe salt it contains helps it to dissolve more oxygen than it otherwise would.
BIt limits animals’ ability to communicate by interfering with their hormones.
CIt includes many substances that animals need.
DIts oxygen is taken in by the gills of many sea animals.
5
Few animals just sit, or move aimlessly along, waiting for good things, like food or mates, or dangerous things, like predators, to come their way. They sense their environment and change their physiology or behavior, and they communicate with each other. One can sense and communicate through a variety of channels, primarily what we call the five senses: touch, taste, smell, hearing, and sight. Moving from the air to water changes the relative benefit of each of the senses. Chemical signals are not dispersed as widely or as predictably under water as in air, so taste and smell have less value for marine animals. Some penguins seem to be able to smell areas with high concentrations of organisms and swim toward them over large ranges, but, tellingly, they do so by smelling the air that they breathe, not by tasting the water that they swim through, even though the organisms they are aiming for are in the water. Sight is also degraded in the ocean because light is absorbed by water. At depths of a few hundred meters there is virtually no light, even in the middle of the day, and even just beneath the surface one can rarely see more than about twenty meters, less than the length of a blue whale.
The word “primarily” in the passage is closest in meaning to
Anormally
Bcommonly
Cparticularly
Dmainly
6
Few animals just sit, or move aimlessly along, waiting for good things, like food or mates, or dangerous things, like predators, to come their way. They sense their environment and change their physiology or behavior, and they communicate with each other. One can sense and communicate through a variety of channels, primarily what we call the five senses: touch, taste, smell, hearing, and sight. Moving from the air to water changes the relative benefit of each of the senses. Chemical signals are not dispersed as widely or as predictably under water as in air, so taste and smell have less value for marine animals. Some penguins seem to be able to smell areas with high concentrations of organisms and swim toward them over large ranges, but, tellingly, they do so by smelling the air that they breathe, not by tasting the water that they swim through, even though the organisms they are aiming for are in the water. Sight is also degraded in the ocean because light is absorbed by water. At depths of a few hundred meters there is virtually no light, even in the middle of the day, and even just beneath the surface one can rarely see more than about twenty meters, less than the length of a blue whale.
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.
APenguins that seem to be able to sense high concentrations of organisms over large ranges do so by smelling the air rather than tasting the water.
BSome penguins can sense areas of high concentrations of organisms and swim toward them over large ranges.
CSome penguins sense organisms by smelling the air they breathe, while others do so by tasting the water they swim through.
DSome penguins seem to be able to sense areas with high concentrations of organisms, but only when both the penguins and the organisms are in the water.
7
One sense that does do better underwater is sound. Sound travels about four times faster than in air. More important, and in contrast to light, sound is less weakened by water than air. While there are a few sounds of terrestrial mammals that travel over kilometers— the roars of lions, the rumbles of elephants, and the howls of wolves—most sounds of most terrestrial mammals are lost at much shorter ranges. Many underwater sounds of marine mammals, on the other hand, can be heard in quiet conditions at a kilometer and some travel very much farther.
The phrase “in contrast to” in the passage is closest in meaning to
Amore than
Bapart from
Calong with
Dunlike with
8
One sense that does do better underwater is sound. Sound travels about four times faster than in air. More important, and in contrast to light, sound is less weakened by water than air. While there are a few sounds of terrestrial mammals that travel over kilometers— the roars of lions, the rumbles of elephants, and the howls of wolves—most sounds of most terrestrial mammals are lost at much shorter ranges. Many underwater sounds of marine mammals, on the other hand, can be heard in quiet conditions at a kilometer and some travel very much farther.
Which of the following can be inferred from the passage about “the roars of lions, the rumbles of elephants, and the howls of wolves”?
AThey can sometimes be heard by marine mammals.
BThey are some of the farthesttraveling sounds made by land animals.
CThey travel about four times faster than most sounds made by most marine animals.
DThey can be heard over a much greater range than sounds made by marine animals.
9
Few animals just sit, or move aimlessly along, waiting for good things, like food or mates, or dangerous things, like predators, to come their way. They sense their environment and change their physiology or behavior, and they communicate with each other. One can sense and communicate through a variety of channels, primarily what we call the five senses: touch, taste, smell, hearing, and sight. Moving from the air to water changes the relative benefit of each of the senses. Chemical signals are not dispersed as widely or as predictably under water as in air, so taste and smell have less value for marine animals. Some penguins seem to be able to smell areas with high concentrations of organisms and swim toward them over large ranges, but, tellingly, they do so by smelling the air that they breathe, not by tasting the water that they swim through, even though the organisms they are aiming for are in the water. Sight is also degraded in the ocean because light is absorbed by water. At depths of a few hundred meters there is virtually no light, even in the middle of the day, and even just beneath the surface one can rarely see more than about twenty meters, less than the length of a blue whale.
[■] One sense that does do better underwater is sound. [■] Sound travels about four times faster than in air. [■] More important, and in contrast to light, sound is less weakened by water than air. [■] While there are a few sounds of terrestrial mammals that travel over kilometers— the roars of lions, the rumbles of elephants, and the howls of wolves—most sounds of most terrestrial mammals are lost at much shorter ranges. Many underwater sounds of marine mammals, on the other hand, can be heard in quiet conditions at a kilometer and some travel very much farther.
Look at the four squaresthat indicate where the following sentence could be added to the passage
There are a couple of reasons for this.
Where would the sentence best fit？Click on a square sentence to the passage.
10
The properties of water determine the properties of life-forms that live in the ocean.
ABecause of the density of water, marine organisms do not need to overcome gravity, but the water’s density causes extreme pressures in the deep ocean that can be a problem for life.
BMarine animals must deal with salt, hormones from other animals, and other harmful substances dissolved in seawater, and they require oxygen to power this process.
CAlthough its concentration in seawater is low, oxygen is the most important dissolved substance for marine life, and most marine animals collect it using gills.
DOxygen in the ocean is much more concentrated near the surface, so many creatures rise toward the surface when they need the energy to move more quickly.
EOne sense that marine animals have available that terrestrial animals lack is chemical signaling, since chemicals easily dissolve in water and can be distributed over large areas.
FThe relative importance of the senses is different underwater, with sight, smell, and taste being less useful than they are on land, and hearing being much more effective.
