讲解:根据文章第一段的句子"In the past 500 years, there have been five mass extinctions, and scientists now believe that we are in the middle of a sixth one.",可知文章主要讲述的是第六次物种灭绝的原因。在文章的后续部分中提到了由于人类活动导致的栖息地丧失,所以可以选出D) Loss of habitat 作...
Of the Big Five, the Triassic-Jurassic extinction has the fewest number of scientists currently researching it, "although that's changing right now," said Columbia University paleoecologist Paul Olsen. Its cause remains under great debate, with the best contender so far being the massive volcanic...
nighttimesleeptobecomefragmentedandthatmissingoutonnighttimesleepcancausesevere daytimesleepiness. “Often,napscontinuinglongarelessrestorativethanmorebriefdaytimenaps;peopleoften wakeupunrefreshedafteralongnap,”sheadds.“Additionally,longdaytimenapstakeawaytime fromotherhealthythingsthatpeopleenjoyduringtheday:spendingtim...
Garbage classification, which is a good way to protect our environment, can't be overemphasized.It can help separate recyclable waste, which can be fully utilized to help save the resources to a large extent. Not only can we make our env...
cancauseheartdiseaseandcancer. A.Whataboutplasticwaterbottles? B.Theycanmakeyougetsickmoreeasily. C.Isitsafeforyoutodrinkthewaterlater? D.Butyoumayfindthatittastesstrange. E.Somepeopleprefertodrinkwaterfromrivers. F.Youmightwanttodrinkitthenextmorning. G.Thisis OK—however,tap watercannotbe storedfor...
end a lot of lives结束很多人的生命;leave millions of people homeless让数百万的人无家可归;pollute the environment污染环境;break up some families让很多家庭破碎;slow down economic development减缓经济发展;destroy buildings and cities 破坏建筑和城市;cause the extinction of some species 导致一些物种灭绝;...
In complete rock units, the best we can say is that dinosaur extinction took less than 100,000 years. In rock units where the sections are less complete, the time frame is longer-even as much as a million years. In marine rocks (rocks formed in seas or oceans) the record is often ...
A research team, led by scientists from Arizona State University and funded by NASA and the National Science Foundation, is helping to unravel this mystery and understand why this extinction event happened, what it can tell us about our origins, and how the world as we know it came to be....
Looking at modern examples, some tipping points that lead to the extinction of a species become obvious.Reduced population sizes is one such factor. As the number of individuals of a species dwindles, it can lead to reduced genetic diversity and greater susceptibility to random catastrophic events...
In terms of genetic drift, how does allele frequency affect the number of generations it takes for the fixation/extinction of that allele? Describe how gene flow, mutation, nonrandom mating and natural selection can cause microevolution...