更多"Isn’t it surprising that scientists"的相关试题:
[单项选择]Isn’t it surprising that scientists have a better understanding of how many stars there are in the galaxy (银河系) than how many species there are on Earth Their estimates of global species diversity vary from 2 to 100 million species. Most people agree on an estimate of somewhere near l0 million and yet only 1.75 million have actually been named. Current knowledge of species diversity is limited. This problem becomes more serious because there is a lack of a central database or list of the world’s species.
New species are still being discovered — even new birds and mammals(哺乳动物). On average, about three new species of birds are found each year, and since 1990, 10 new species of monkeys have been discovered. Other groups are still far from being completely described: an estimated 40 percent of freshwater fishes in South America have not yet been classified.
Scientists were started in 1980 by the discovery of a huge diversity of insects in tropical forests. In one study of just 1
A. About 2 million.
B. About 10 million.
C. About 100 million.
D. About 1.75 million.
[填空题]Thinner isn’t always better. A number of studies have __1___ that normal-weight people are in fact at higher risk of some diseases compared to those who are overweight. And there are health conditions for which being overweight is actually ___2___. For example, heavier women are less likely to develop calcium deficiency than thin women. ___3___ among the elderly, being somewhat overweight is often an ___4___ of good health.
Of even greater ___5___ is the fact that obesity turns out to be very difficult to define. It is often defined ___6___ body mass index, or BMI. BMI ___7__ body mass divided by the square of height. An adult with a BMI of 18 to 25 is often considered to be normal weight. Between 25 and 30 is overweight. And over 30 is considered obese. Obesity, ___8___,can be divided into moderately obese, severely obese, and very severely obese.
While such numerical standards seem 9 , they are not. Obesity is probably less a matter of weight than body fat. Some people with a h
A. A．in terms of
B．in case of
C．in favor of
D．in respect of
