单词:populations
n. a group of organisms of the same species inhabiting a given area
n. (statistics) the entire aggregation of items from which samples can be drawn
单词:populations 相关文章
Scientists Find No Evidence of Yeti For decades, a large creature called a Yeti has been talked about in Western popular culture. It has appeared in films, cartoons, video games and more. 几十年来,西方流行文化一直提到了一种名为雪人
This is Scientific American Sixty Seconds Science, I'm Sophie Bushwick, got a minute? When Mexican tetra fish moved into darker caves long ago, they evolved to deal with the dark by becoming albino and going blind. A new research shows that the chang
(WA) Human populations near the equator have evolved dark skin over many generations because of exposure to the fierce rays of the Sun. A similar phenomenon has also occurred in other parts of the animal kingdom. The African grass mouse is a good ex
Todd: What do you think about the zoo? Dianna: I like to go to the zoo. I like to give all the animals names, like Bert the Giraffe, but I wish the animals didn't have to be in the zoo, but I think it is good when zoos save animals, and help to make
We are living on a planet with a lot of activities, with reference to our living environment,done by faith and guess alone. 我们对于这个地球上所发生的许多现象,都只是通过信念或猜测来认知。 Our lives depend upon these cre
This is Scientific American's 60-second Science. I'm Cynthia Graber, this will just take a minute. Sex might seem like one of those little gifts from evolution. But its pretty inefficient from an evolutionary perspective. Itd be much easier to reprod
Todd: What do you think about the zoo? Dianna: I like to go to the zoo. I like to give all the animals names, like Bert the Giraffe, but I wish the animals didn't have to be in the zoo, but I think it is good when zoos save animals, and help to make
By Brian Wagner Miami, Florida 15 August 2007 U.S. minority population are expanding New data from the U.S. Census Bureau shows that black, Asian, Hispanic and other minority populations are expanding in many districts where whites were once dominant
This is Scientific American's 60-Second Science. I'm Steve Mirsky . Got a minute ? February 12th is the 200th birthday of Charles Darwin and Abraham Lincoln. But theyre linked by something else, too. Before Darwin, natural philosophers held to a poin
[00:00.40]It's becoming more and more of a problem [00:02.99]worldwide,isn't it? [00:04.33]Yes,I quite agree. [00:06.27]But noise pollution is generally [00:08.19]only a problem in urban areas. [00:10.79]This is because of increasing industrializatio
This is the VOA Special English Agriculture Report. A study from Canada says fish farms are a threat to some populations of wild salmon. It says the danger is from sea lice, which are small organisms that feed on fish. The researchers say these para
Bat Populations Still in Decline Bats are an amazingly diverse group of flying mammals that can be found in virtually every corner of the world. Because they're mostly nocturnal and a few types feed on animal blood, bats have acquired a rather dark r
Todd: What do you think about the zoo? 你觉得动物园怎么样? Dianna: I like to go to the zoo. I like to give all the animals names, like Bert the Giraffe, but I wish the animals didn't have to be in the zoo, but I think it is good when zoos
The second story has to do with something that I'm sure most of you have seen or will remember. 第二个故事,和那些我相信你们大多数人都见过或者记得相关事情。 Very often, countries in Africa suffer drought and floods, 非洲
Tasmanian Devils, pygmy-possums and native parrots are just some of Australia's threatened species. But thanks to a successful breeding season, one animal sanctuary is optimistic for the future survival of these creatures. Our reporter Li Dong has th
They are extremely awkward on land, and not exactly graceful in the water. But there's something endearing about these egg-laying mammals. Platypuses can only be found in the rivers, streams and lakes along the east coast of Australia. But they range
Human demands on natural resources have doubled in under 50 years and are now outstripping(超过) what the Earth can provide by more than half, a new report has warned. And humanity carries on(继续) as it is in use of resources, globally i
JUDY WOODRUFF: New HIV infections and AIDS-related deaths have fallen so dramatically in recent years that it may be possible to control the epidemic by 2030 and eventually end it altogether. That's the projection in a new U.N. report released in adv
DNA Testing to Help Sharks Keep Fins In a study in the journal Endangered Species Research, shark fins on sale were shown to be from a specific region in which shark populations have collapsed, evidence that may help change fishing regulations. Cynth
回顾托福阅读的所有题型,其中有2种题型占据的比例最高----词汇题和事实信息题,前者每一场考试大约考察10-12题左右,而后者大约也会考察12题左右。因此,从每一场考试的39-42题总量上来看