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A) feeble
B) extinct
C) massive
D) extinguished
答案
更多“Certain species disappeared or became ________ as new forms arose that were better”相关的问题
第1题
However, the first two phases of the conservation movement had serious limitations. The new laws allowed certain animals to increase so much that they actually "ate up" their habitat. Many of them starved to death because the land simply could not provide for them all. Something had to be done. This is how careful wildlife management came into being.
One of the chief concerns of wildlife management is the protection and improvement of the natural habitat so that animals have enough food and water to survive. Wildlife management involves care of the soil to produce good vegetation. It involves care of plants and bushes, not only as a source of food, but also as protection. Animals needs cover to hide from their natural enemies and to raise their young safely.
Just as crops are harvested, wildlife too must sometimes be "harvested." By allowing limited hunting and fishing, good management can control certain species that threaten to overpopulate their habitat.
Another major part of the wildlife management is the increasing of certain species by artificial means. Some creatures, like the whooping crane, were brought back from the edge of extinction in this way. In order to save these species, members of wildlife teams have reared the young in the safety of research stations.
The passage is mainly about ______.
A．the history of the wildlife conservation movemen
B．the preservation of wildlife through laws
C．wildlife management as a new approach
D．protection and improvement of the habitat of animals
第2题
M: Oh well, congratulations. I hope you were rewarded handsomely.
W: Well, every bit helps. So, about your lecture, I understand you were talking about extinctions.
M: Yes. Well, the crux of my talk was just that, we tend to think of extinction as a dramatic event, but most species die out over quite a period of time.
W: Why do they die off？ I thought they were continuously improving themselves. Natural selection, I think you once mentioned.
M: Ah, but you see while there is natural competition between the species, what determines which species survive is largely by chance.
W: I don't get it. Why do species bother competing？
M: Well, there are short-term advantages. But many species also are helped by others. For example, the common housefly and cockroaches might have died off years ago if not for humans.
W: But you're not saying that humans are so successful merely because of chance？
M: To a certain extent, humans were initially lucky enough to have the right weather conditions and a lack of predators, but now, of course, we survive by ingenuity!
W: So we may never become extinct.
M: NO, because we may be in a crash course to extinction by our continuous exploitation of the environment. We are a relatively young species and our time is not yet overdue.
W: But there are 6 billion of us.
M: Yes, and there're many more houseflies too! Each with the capacity to spread one disease from one person to another in a fast period of time.
(23)
A．She is writing a competitive paper for a scholarship.
B．She is doing a paper.
C．She missed the lecture.
D．She is planning to attend the scholarship award ceremony.
第3题
听力原文：W: Professor Marnes, I wonder if you can fill me in on your lecture last Friday. I had to attend a scholarship award ceremony.
M: Oh well, congratulations. I hope you were rewarded handsomely!
W: Well, every bit helps. So, about your lecture, I understand you were talking about extinctions.
M: Yes. Well, the crux of my talk was just that we tend to think of extinction as a dramatic event, but most species die out over quite a period of time.
W: Why do they die off？ I thought they were continuously improving themselves. Natural selection, I think you once mentioned.
M: Ah, but you see while there is natural Competition between the species, what determines which species survive is largely by chance.
W: I don't get it. Why do species bother competing？
M: Well, there are short-term advantages. But many species also are helped by others. For example, the common housefly and cockroaches might have died off years ago if not for humans.
W: But you're not saying that humans are so successful merely because of chance？
M: To a certain extent, humans were initially lucky enough to have the right weather conditions and a lack of predators, but now, of course, we survive by ingenuity!
W: go we may never become extinct.
M: No, because we may be in a crash course to extinction by our continuous exploitation of the environment. We are a relatively young species and our time is hot yet overdue.
W: But there are 6 billion of us!
M: Yes and there're many more houseflies too! Each with the capacity to spread one disease from one person to another in a fast period of time.
(20)
A．She is writing a competitive paper for a scholarship.
B．She is doing a paper.
C．She missed the lecture.
D．She is planning to attend the scholarship award ceremony.
第4题
1.This passage is most probably written as ____.
A、the beginning part of a certain chapter
B、the middle part of a certain chapter
C、the last part of a certain chapter
D、a self-contained chapter
2.Which of the following topics is NOT discussed in the passage？ ____
A、Natural Resources
B、Industrial Pollution
C、Unemployment
D、Overpopulation
3.The author's purpose in the first paragraph is to tell us the fact that ____.
A、deserts are hostile
B、Antarctic is very cold
C、human beings now inhabit the entire Earth
D、there are many different species on planet Earth
4.According to the passage, some natural resources like fuels and metals ____.
A、are no longer new
B、will never be gone
C、will soon be used up
D、can not be used at present
5.The phrase `strive for' in the second paragraph means ____.
A、fight with each other in order to get'
B、make great efforts to achieve'
C、have a violent struggle because of'
D、suffer a lot from'
6.Which pollution is NOT mentioned in the passage？ ____
A、Air Pollution
B、Water Pollution
C、Soil Pollution
D、Sound Pollution
第6题
Although the fact that today viruses are known to 【S1】______
cause cancer in animals and in certain plants, that exists 【S2】______
a great reluctance to accept viruses as being of importance
in human cancer.
Basic biological phenomena generally do not
differ strikingly as one goes from one species through 【S3】______
another. It should be recognize that caner is a biological 【S4】______
problem and not a problem that is unique for man.
Cancer originates when a normal cell suddenly becomes
a cancer cell which multiplys widely and without 【S5】______
apparent restraint. Cancer may originate in many different
kind of cell, but the cancer cell usually continues 【S6】______
to carry certain traits of the cell of origin. The
transformation of a normal cell into a cancer cell may have
less than one kind of cause, but there is good reason to 【S7】______
consider the relationships that exist between viruses
and cancer.
Since there is no evidence which human cancer, as 【S8】______
generally experience, is infectious, many persons
believe that because viruses are infectious agents they
cannot possibly be of importance in human cancer.
However, viruses can mutate and examples are known
in which a virus that never kills its host can mutate to
form. a new strain of virus that always kills its host. It
does not seem unreasonable assume that an innocuous 【S9】______
latent virus might mutate to form. a strain that causes
cancer. Certainly the experiment evidence now available 【S10】______
is consistent with the idea that viruses as we know
them today, could be the causative agents of most, if not
all cancer, including cancer in man.
【S1】
第7题
A.Higher temperature causes the low biodiversity of marine invertebrates．
B.Fossil record can represent a relatively believable history of life．
C.The number of fossils was higher during greenhouse phases．
D.Global warming might promote the richness of species on Earth．
第9题
Why leaves change colors
If you are lucky, you live in one of those parts of the world where Nature has one last fun before settling down into winter's sleep. In those lucky places, as days shorten and temperatures become crisp, the quiet green palette(调色板) of summer leaves is transformed into the vivid autumn palette of reds, oranges, golds, and browns before the leaves fall off the trees. On special years, the colors are truly breathtaking,
How does autumn color happen？
For years, scientists have worked to understand the changes that happen to trees and shrubs in the autumn. Although we don't know all the details, we do know enough to explain the basics and help you to enjoy more fully Nature's multicolored autumn farewell. Three factors influence autumn leaf color-leaf pigments(色素), length of night, and weather, but not quite in the way we think. The timing of color change and leaf fall is primarily regulated by the calendar. That is, the increasing length of night. None of the other environmental in flounces -temperature, rainfall, food supply, and so on—are as unvarying as the steadily increasing length of night during autumn. As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to paint the landscape with Nature's autumn palette.
Where do autumn colors come from？
-A color palette needs pigments, and there are three types that are involved in autumn color. Chlorophyll(叶绿素),which gives leaves their basic green color. It is necessary for photosynthesis(光合作用), the chemical reaction that enables plants to use sunlight to manufacture sugars for their food.
-Carotenoids(类胡萝卜素), which produce yellow, orange, and brown colors in such things as corn, carrots, and daffodils.
-Anthocyanins(花青素), which give color to such familiar things as red apples, grapes, blue berries, cherries, strawberries, and plums. They are water soluble and appear in the watery liquid of leaf cells.
Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.
During the growing season, chlorophyll is continually being produced and broken down and leaves appear green. As night length increases in the autunm, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanins that are present in the leaf are then unmasked and show their colors.
Certain colors are characteristic of particular species. Oaks turn red, brown, or russet; hickories, golden bronze; aspen and yellow-poplar, golden yellow; dogwood, purplish red. Maples differ species by species: red maple turns brilliant scarlet; sugar maple, orange-red; and black maple, glowing yellow. Leaves of some species such as the elms simply shrink and fall, exhibiting little color.
The timing of the color change also varies by species. Sourwood in southern forests can become vividly colorful in late summer while all other species are still vigorously green. Oaks put on their colors long after other species have already shed their leaves. These differences in timing among species seem to be genetically inherited, for a particular species at the same latitude will show the same coloration in the cool temperatures of high mountains at about the same time as it does in warmer lowlands.
How does weather affect autumn color？
The amount and brilliance of the colors that develop in any particular autumn season are related to weather conditions that occur before and during the time the chlorophyll in the leaves is decreasing. Temperature and moisture are the main influences. A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most specta
A．Y
B．N
C．NG
第10题
Professor Charles R. Schwenk’s research shows ________.
A) the advantages and disadvantages of conflict
B) the real value of conflict
C) the difficulty in determining the optimal level of conflict
D) the complexity of defining the roles of conflict
