tpo26-2阅读纯答案
tpo26-2阅读纯答案：Survival of Plants and Animals in Desert Conditions
PARAGRAPH 1
The harsh conditions in deserts are intolerable for most plants and animals. Despite theseconditions, however, many varieties of plants and animals have adapted to deserts in a numberof ways. Most plant tissues die if their water content falls too low: the nutrients that feed plantsare transmitted by water; water is a raw material in the vital process of photosynthesis; andwater regulates the temperature of a plant by its ability to absorb heat and because watervapor lost to the atmosphere through the leaves helps to lower plant temperatures. Watercontrols the volume of plant matter produced. The distribution of plants within different areasof desert is also controlled by water. Some areas, because of their soil texture, topographicalposition, or distance from rivers or groundwater, have virtually no water available to plants,whereas others do.
PARAGRAPH 2
The nature of plant life in deserts is also highly dependent on the fact that they have to adaptto the prevailing aridity. There are two general classes of vegetation: long-lived perennials,which may be succulent (water-storing) and are often dwarfed and woody, and annuals orephemerals, which have a short life cycle and may form a fairly dense stand immediately afterrain.
PARAGRAPH 3
The ephemeral plants evade drought. Given a year of favorable precipitation, such plantswill develop vigorously and produce large numbers of flowers and fruit. This replenishes theseed content of the desert soil. The seeds then lie dormant until the next wet year, when thedesert blooms again.
PARAGRAPH 4
The perennial vegetation adjusts to the aridity by mear of various avoidance mechanisms.Most desert plants are 11 probably best classified as xerophytes. They possess drought-resisting adaptations: loss of water through the leaves is reduced by means of dense hairscovering waxy leaf surfaces, by the closure of pores during the hottest times to reduce waterloss, am by the rolling up or shedding of leaves at the beginning of the dry season. Somexerophytes, the succulents (including cacti), store water in their structures. Another way ofcountering drought is to have a limited amount of mass above ground and to have extensiveroot networks below ground. It is not unusual for the roots of some desert perennials toextend downward more than ten meters. Some plants are woody in type — an adaptationdesigned to prevent collapse of the plant tissue when water stress produces wilting. Anotherclass of desert plant is the phreatophyte. These have adapted to the environment by thedevelopment of long taproots that penetrate downward until they approach the assuredwater supply provided by groundwater. Among these plants are the date palm, tamarisk, andmesquite. They commonly grow near stream channels, springs, or on the margins of lakes.
PARAGRAPH 5
Animals also have to adapt to desert conditions, and they may do it through two forms ofbehavioral adaptation: they either escape or retreat. Escape involves such actions asaestivation, a condition of prolonged dormancy, or torpor, during which animals reduce theirmetabolic rate and body temperature during the hot season or during very dry spells.
PARAGRAPH 6
Seasonal migration is another form of escape, especially for large mammals or birds. The termretreat is applied I to the short-term escape behavior of desert animals, and it usuallyassumes the pattern of a daily rhythm. Birds shelter in nests, rock overhangs, trees, anddense shrubs to avoid the hottest hours of the day, while mammals like the kangaroo ratburrow underground.
PARAGRAPH 7
Some animals have behavioral, physiological, and morphological (structural) adaptations thatenable them to withstand extreme conditions. For example, the ostrich has 1 plumage that isso constructed that the feathers are long but not \ too dense. When conditions are hot, theostrich erects them on its 1 back, thus increasing the thickness of the barrier between solarradiation and the skin. The sparse distribution of the feathers, however, also allowsconsiderable lateral air movement over the skin surface, thereby permitting further heatloss by convection.Furthermore, the birds orient themselves carefully with regard to the Sunan0 gently flap their wings to increase convection cooling.
PARAGRAPH 1
The harsh conditions in deserts are intolerable for most plants and animals. Despite theseconditions, however, many varieties of plants and animals have adapted to deserts in a numberof ways. Most plant tissues die if their water content falls too low: the nutrients that feed plantsare transmitted by water; water is a raw material in the vital process of photosynthesis; andwater regulates the temperature of a plant by its ability to absorb heat and because watervapor lost to the atmosphere through the leaves helps to lower plant temperatures. Watercontrols the volume of plant matter produced. The distribution of plants within different areasof desert is also controlled by water. Some areas, because of their soil texture, topographicalposition, or distance from rivers or groundwater, have virtually no water available to plants,whereas others do.
1、According to paragraph 1, water provides all of the following essential functions for plantsEXCEPT
improving plants' ability to absorb sunlight
preventing plants from becoming overheated
transporting nutrients
serving as a raw material for photosynthesis
PARAGRAPH 3
The ephemeral plants evade drought. Given a year of favorable precipitation, such plantswill develop vigorously and produce large numbers of flowers and fruit. This replenishes theseed content of the desert soil. The seeds then lie dormant until the next wet year, when thedesert blooms again.
2、Paragraph 3 suggests that during a dry year ephemerals
produce even more seeds than in a wet year
do not sprout from their seeds
bloom much later than in a wet year
are more plentiful than perennials
PARAGRAPH 2
The nature of plant life in deserts is also highly dependent on the fact that they have to adaptto the prevailing aridity. There are two general classes of vegetation: long-lived perennials,which may be succulent (water-storing) and are often dwarfed and woody, and annuals orephemerals, which have a short life cycle and may form a fairly dense stand immediately afterrain.
PARAGRAPH 3
The ephemeral plants evade drought. Given a year of favorable precipitation, such plantswill develop vigorously and produce large numbers of flowers and fruit. This replenishes theseed content of the desert soil. The seeds then lie dormant until the next wet year, when thedesert blooms again.
3、How is paragraph 2 related to paragraph 3?
Paragraph 2 provides a general description of desc plants, and paragraph 3 provides ascientific explanation for these observations.
Paragraph 2 divides desert plants into two categories, and paragraph 3 provides furtherinformation about one of these categories.
Paragraph 2 proposes one way of dividing desert plants into categories, and paragraph 3explains one problem with this method of classification.
Paragraph 2 discusses two categories of desert plants, and paragraph 3 introduces a thirdcategory of plants.
4、 In saying that ephemerals will develop "vigorously" when there is favorable precipitation,the author means that their development will be
sudden
early
gradual
strong
healthy
PARAGRAPH 4
The perennial vegetation adjusts to the aridity by mear of various avoidance mechanisms.Most desert plants are 11 probably best classified as xerophytes. They possess drought-resisting adaptations: loss of water through the leaves is reduced by means of dense hairscovering waxy leaf surfaces, by the closure of pores during the hottest times to reduce waterloss, am by the rolling up or shedding of leaves at the beginning of the dry season. Somexerophytes, the succulents (including cacti), store water in their structures. Another way ofcountering drought is to have a limited amount of mass above ground and to have extensiveroot networks below ground. It is not unusual for the roots of some desert perennials toextend downward more than ten meters. Some plants are woody in type — an adaptationdesigned to prevent collapse of the plant tissue when water stress produces wilting. Anotherclass of desert plant is the phreatophyte. These have adapted to the environment by thedevelopment of long taproots that penetrate downward until they approach the assuredwater supply provided by groundwater. Among these plants are the date palm, tamarisk, andmesquite. They commonly grow near stream channels, springs, or on the margins of lakes.
5、The word "countering" in the passage is closest in meaning to
eliminating
making use of
acting against
experiencing
6、According to paragraph 4, some desert plants with root systems that are extraordinarily welldeveloped have
relatively little growth aboveground
very leafy aboveground structures
nonwoody plant tissue resistant to wilting
water stored within their roots
7、The word "assured" in the passage is closest in meaning to
pure
diminished
guaranteed
deep
8、What do "the date palm, tamarisk, and mesquite" have in common?
They are always found together.
They depend on surface water provided by streams, springs, and lakes.
They are phreatophytes.
Their roots are capable of breaking through hard soils
PARAGRAPH 5
Animals also have to adapt to desert conditions, and they may do it through two forms ofbehavioral adaptation: they either escape or retreat. Escape involves such actions asaestivation, a condition of prolonged dormancy, or torpor, during which animals reduce theirmetabolic rate and body temperature during the hot season or during very dry spells.
9、 Which of the sentences below best expresses the essential information in the highlighted 1sentence in the passage? Incorrect choices change the meaning in important ways or leave outessential information.
One way animals escape is by entering a state of extended dormancy, known as aestivation,during the hottest and driest times of year.
Animals can escape without using direct action, or aestivation, simply by reducing theirmetabolic rate and body temperature.
The actions that an animal uses to escape are known as aestivation, which sometimes involvesa reduction in metabolic rate or body temperature.
When the weather is especially hot and dry, an animal may suffer from a condition known asaestivation, at which point the animal needs to escape.
10、It can be inferred from paragraph 5 that all of the places desert animals retreat to
provide shade from the sun
sometimes become crowded
are places where supplies of food are plentiful
leave the animals vulnerable to predators
PARAGRAPH 7
Some animals have behavioral, physiological, and morphological (structural) adaptations thatenable them to withstand extreme conditions. For example, the ostrich has 1 plumage that isso constructed that the feathers are long but not \ too dense. When conditions are hot, theostrich erects them on its 1 back, thus increasing the thickness of the barrier between solarradiation and the skin. The sparse distribution of the feathers, however, also allowsconsiderable lateral air movement over the skin surface, thereby permitting further heatloss by convection.Furthermore, the birds orient themselves carefully with regard to the Sunan0 gently flap their wings to increase convection cooling.
11、According to paragraph 7, what special adaptation helps the ostrich cope with hot desertconditions?
Each of its feathers is very short and dense.
Its wings produce only lateral air movement when flapping.
Its feathers are very thickly set on both its back and its wings.
It can make its feathers stand up on its If back.
12、Look at the four squares that indicate where the following sentence could be added to thepassage.
The increase in reward still did not attract young people to this hard life, and convicted criminalsand slaves were pressed into services
Where would the sentence best fit?
PARAGRAPH 1
The harsh conditions in deserts are intolerable for most plants and animals. Despite theseconditions, however, many varieties of plants and animals have adapted to deserts in a numberof ways. Most plant tissues die if their water content falls too low: the nutrients that feed plantsare transmitted by water; water is a raw material in the vital process of photosynthesis; andwater regulates the temperature of a plant by its ability to absorb heat and because watervapor lost to the atmosphere through the leaves helps to lower plant temperatures. Watercontrols the volume of plant matter produced. The distribution of plants within different areasof desert is also controlled by water. Some areas, because of their soil texture, topographicalposition, or distance from rivers or groundwater, have virtually no water available to plants,whereas others do.
13. Directions: From the seven statements below, select the statements that correctlycharacterize breathing during wakefulness and those statements that correctly characterizebreathing during sleep. Drag each answer choice you select into the appropriate box of thetable. Two of the answer choices will NOT be used. This question is worth 3 points.
Adaptations of Annuals BF
Five of the phrases will NOT be used.
A. Woody structures
B. Explosive growth in wet years
C. Long, thin, shallow roots
D. Storage of water in plant tissue
E. Minimization of the amount of water used for
Adaptations of Perennials ADG
Four of the phrases will NOT be used,
A. Woody structures
B. Explosive growth in wet years
C. Long, thin, shallow roots
D. Storage of water in plant tissue
E. Minimization of the amount of water used for photosynthesis
F. Short life cycle
G. Leaves designed to minimize water loss