Why is the world's population growing? The answer is not what you might think. In 1900, people died at the average (平均的) age of 30. By 2000 the average age was 65. But while increasing health was obvious of the 20th century, declining (下降的) birth rate could be more obvious ...
The population clock never stops ticking--there are already 6.4 billion of us and the latest estimates predict around 9.3 billion by 2050. Yet back in 1900, world population was just 1.6 billion. So what has driven this period of startling growth?
Five hundred years ago,the population of the world was about 460 million.In 1900,the world's population was under 2 billion (十亿).Right now it is doubling every 40 years.That means,if this rate of growth continues,when you are a parent,there will be twice as many people on earth as...
have been reproducing like rabbits,but that people have stopped dropping dead like flies.In 1900,people died at the average age of 30.By 2000 the average age was 65.But while increasing health was a typical feature of the 20th century,declining birth rate could be a defining one of the ...
The answer is not what you might think.The reason for the explosion is not that people have been reproducing like rabbits,but that people have stopped dropping dead like flies.In 1900,people died at the average age of 30.By 2000 the average age was 65.But while increasing health was a ...
The answer is not what you might think.The reason for the explosion is not that people have been reproducing like rabbits,but that people have stoppe d dropping dea d like flies.In 1900,people die d at the average age of 30.By 2000 the average age was 65.But while increasing health ...
In the early 1900s, there were more electric cars on the road than there were petrol (汽油) cars. At that time, petrol was 56. expensive compared with other fuels (燃料). 57. When petrol prices dropped and new technologies were developed, electric cars went out of fashion (过时). ...
Toward the 19th century,scientists found they needed to protect the animals, 9 they created national parks. The first national park in the world was Yellowstone. 10 ,now there are more than 100 national parks in 120 countries to protect animals. ...
The answer is not what you might think. The reason for the explosion is not that people _1_(reproduce) like rabbits, but that people have stoppe d _2(drop)de a d like flies. In 1900, people die d _3 the average age of 30. By 2000 the average age was 65. But while increasing...
Plutocracies have been present since ancient times; the Roman Empire was considered a form of plutocracy in which a senate consisting of the wealthy aristocracy had the power to elect local administration officials and propose new policies. ...