请输入或粘贴题目内容
搜题
拍照、语音搜题，请扫码下载APP
题目内容
（请给出正确答案）
A．Because elephants are difficult to catch
B．Because it is not possible to count elephants from a plane
C．Because it is not possible to keep track of elephants
D．Because elephants are shy animals
答案
更多“Why do researchers estimate elephant numbers in an area by counting dung piles？（”相关的问题
第1题
Why do researchers estimate elephant numbers in an area by counting dung piles？
A．Because elephants are difficult to catch.
B．Because it is not possible to count elephants from a plane.
C．Because it is not possible to keep track of elephants.
D．Because elephants are shy animals.
第2题
Why do researchers estimate elephant numbers in an area by counting dung piles？
A．Because elephants are difficult to catch
B．Because it is not possible to count elephants from a plane．
C．Because it is not possible to keep track of elephants．
D．Because elephants are shy animals
第3题
Why do researchers develop a new device to monitor signs of landsides？
A.Because the new device can measure the site directly
B.Because the new device can be sunk into boreholes or fixed above ground
C.Because the common methods can cause false alarms
D.Because the common methods are useless
第4题
37 Why do researchers estimate elephant numbers in an area by counting dung piles？
A Because elephants are difficult to catch
B Because it is not possible to count elephants from a plane．
C Because it is not possible to keep track of elephants．
D Because elephants are shy animals
第5题
A．Because elephants are difficult to catch.
B．Because it is not possible to count elephants from a plane.
C．Because it is not possible to keep track of elephants.
D．Because elephants are shy animals.
第6题
A．Because there is early oxygen transfer.
B．Because they do not form. their images quickly enough to follow such rapid changes.
C．Because researchers control the changes in blood flow.
D．Because early oxygen transfer gives the flow blood energy.
第7题
Why do drinkers earn more than teetotalers according to this passage？
A．Because drinkers have better health.
B．Because drinkers receive more money from social warefare.
C．Because drinkers have wider social networks.
D．Because drinkers are more hard-working.
第8题
Why does cream go bad faster than butter？ Some researchers think they have the answer, and it comes down to the structure of the food, not its chemical composition--a finding that could help rid some processed foods of chemical preservatives.
Cream and butter contain pretty much the same substances, so why cream should sour much faster has been a mystery. Both are emulsions--tiny globules(小球体)of one liquid evenly distributed throughout another. The difference lies in what's in the globules and what's in the surrounding liquid, says Brocklehurst, who led the investigation.
In cream, fatty globules drift about in a sea of water. In butter, globules of a watery solution are locked away in a sea of fat. The bacteria which make the food go bad prefer to live in the watery regions of the mixture. "This means that in cream, the bacteria are free to grow throughout the mixture," he says.
When the situation is reversed, the bacteria are locked away in compartments(隔仓室)buried deep in the sea of fat. Trapped in this way, individual colonies cannot spread and rapidly run out nutrients(养料). They also slowly poison themselves with their waste products. "In butter, you get a self--limiting system which stops the bacteria growing," says Broeklehurst.
The researchers are already working with food companies keen to see if their products can be made resistant to bacterial attack through alterations to the food's structure. Brocklehurst believes it will be possible to make the emulsions used in salad cream, for instance, more like that in butter. The key will be to do this while keeping the salad cream liquid and not turning in into a solid lump.
The significance of Brocklehurst's research is that ______.
A．it suggested a way to keep some foods fresh without preservatives
B．it discovered tiny globules in both cream and butter
C．it revealed the secret of how bacteria multiply in cream and butter
D．it found that cream and butter share the same chemical composition
第9题
Weight Experiment
Nicola Walters has been taking part in experiments in Scotland to discover why humans gain and lose weight. Being locked in a small room called a &39;calorimeter&39; (执着量测量室) is one way to find out.
1. The signs above the two rooms read simply &39;Chamber One&39; and &39;Chamber Two&39;. These are the calorimeters: 4m by 2m white-walled rooms where human volunteers are locked up in the name of science. Outside these rooms another sign reads &39;Please do not enter-work in progress&39; and in front of the rooms advanced machinery registers every move the volunteers make. Each day, meals measured to the last gram are passed through a hole in the wall of the calorimeter to the resident volunteer.
2. Nicola Walters is one of twenty volunteers who, over the past eight months, have spent varying periods inside the calorimeter. Tall and slim, Nicola does not have a weight problem, but thought the strict diet might help with her training and fitness programme. A self-employed community dance worker, she was able to fit the experiment in around her work. She saw an advert for volunteers at her local gym and as she is interested in the whole area of diet and exercise, she thought she would help out.
3. The experiment on Nicola involved her spending one day on a fixed diet at home and the next in the room. This sequence was repeated four times over six weeks. She arrived at the calorimeter at 8:30 am on each of the four mornings and from then on everything she ate or drank was carefully measured. Her every move was noted too, her daily exercise routine timed to the last second. At regular intervals, after eating, she filled in forms about how hungry she felt and samples were taken for analysis.
4. The scientists help volunteers impose a kind of order on the long days they face in the room. The first time, I only took one video and a book, but it was OK because I watched TV the rest of the time, says Nicola. And twice a day she used the exercise bike. She pedaled (踩踏板) for half an hour, watched by researchers to make sure she didn&39;t go too fast:
5. It seems that some foods encourage you to eat more, while others satisfy you quickly. Volunteers are already showing that high-fat diets are less likely to make you feel full. Believing that they may now know what encourages people to overeat, the researchers are about to start testing a high-protein weight-loss diet. Volunteers are required and Nicola has signed up for further sessions.
Paragraph 1 ______
A What does the calorimeter look like inside？
B What program was designed for the experiment？
C What is a calorimeter？
D What is the first impression？
E How do the volunteers kill the time？
F Why did Nicola join in the experiments？
Paragraph 2 ______
A What does the calorimeter look like inside？B What program was designed for the experiment？C What is a calorimeter？D What is the first impression？E How do the volunteers kill the time？F Why did Nicola join in the experiments？
Paragraph 3 ______
A What does the calorimeter look like inside？B What program was designed for the experiment？C What is a calorimeter？D What is the first impression？E How do the volunteers kill the time？F Why did Nicola join in the experiments？
Paragraph 4 ______
A What does the calorimeter look like inside？B What program was designed for the experiment？C What is a calorimeter？D What is the first impression？E How do the volunteers kill the time？F Why did Nicola join in the experiments？
The machinery outside the calorimeters records everything ______.
A the volunteers doB because she does not have a weight problemC because the life there can be very boringD make people overeatE because she was her own bossF after passing a high-protein test
Nicola Walters had time for the experiments ______.
A the volunteers doB because she does not have a weight problemC because the life there can be very boringD make people overeatE because she was her own bossF after passing a high-protein test
Volunteers have to get prepared for the time in the calorimeter ______.
A the volunteers doB because she does not have a weight problemC because the life there can be very boringD make people overeatE because she was her own bossF after passing a high-protein test
The experiments show that high-fat diets ______.
A the volunteers doB because she does not have a weight problemC because the life there can be very boringD make people overeatE because she was her own bossF after passing a high-protein test
请帮忙给出每个问题的正确答案和分析，谢谢！
第10题
Even after centuries of scientific research, no one knows for sure why human beings (plus a few other primates, including chimpanzees, apes, and orangutans) laugh.
2. Even if scientists still do not know why we laugh, they have learned a lot about it. For example: The sound of laughter is created when you inhale deeply and then release the air while your diaphragm moves in a series of short, spasmodic contractions. The typical laugh is made up of pulses of sound that are about 1/15th of a second long and 1/5th of a second apart.
3. One of the most interesting things researchers have learned is the powerful healing effect of laughter. Well, actually they' re re-learning it after centuries of neglect: In the Middle Ages, doctors "treated" their patients by telling them jokes, but modem medicine discounted the curative properties of laughing. That began to change in 1979, when editor Norman Cousins wrote Anatomy of an Illness, in which he credited watching humorous videos with helping him reduce pain and recover from ankylosing spondylitis (类风湿性脊椎炎), a lifethreatening degenerative spinal disease. The book inspired researchers to look into whether laughter really could aid in healing and recovery from illness.
4. In 1995, two researchers at the Loma Linda University School of Medicine had 10 medical students watch a 60-minute videotape of Gallagher, a stand-up comedian famous for smashing watermelons and other objects with a sledgehammer. The researchers found that after watching the video, where was a measurable decrease in stress hormones, including epinephrine and dopamine, in the students' blood, plus an increase in endorphins-the body' s natural painkillers. But the most changes were found in the students' immune systems. These included
&8226; Increased levels of gamma interferon, a hormone that "switches on" the immune system, helps fight viruses and regulates cell growth.
&8226; Increased numbers of "helper T-cells," which help the body coordinate the immune system's response to illness
&8226; More "Compliment 3," a substance that helps antibodies destroy infected and damaged cells
&8226; An increase in the number and activity of "natural killer (NK) cells," which the body uses to attack foreign cells, cancer cells, and cells infected by viruses
5. Some of the levels even began to change before the students watched the video-just from the expectation that they were about to laugh. "Say you' re going to your favorite restaurant," Dr. Berk explains. "You can visualize the food; you can almost taste it. You are already experiencing the physiology of enjoying it. Your immune system [also] remembers. By using humor to combat stress, you can condition yourself to strengthen your immune system."
6. Chimpanzees, apes and a few other primates laugh, but no other animals do Chimps' laugh sounds like rapid panting, but unlike humans, they are unable to regulate or control the air as they breathe out. This lack of ability to control airflow is same thing that deprives them of speech. Chimps and gorillas that have learned sign language have been known to sign one another for laughs
A. The Process of Laughter.
B. Why Laughter Developed？
C. Laughter and Other Creatures.
D. Mordern Breakthrough in Humour for Therapy.
E. Various After-effects of laughing.
F. Anticipatorv Effect on the Immune System.
Paragraph 3. ______
