题目内容
Population and Our Planet
A very important world problem is the increasing number of people who actually inhabit this planet. The limited amount of land and land resources will soon be unable to support the huge population if it continues to grow at its present rate.
So why is this huge increase in population taking place？ It is really due to the spread of the knowledge and practice of what is becoming known as "Death Control". You have no doubt heard of the term "Birth Control". "Death Control" is something rather different. It recognizes the work of the doctors and scientists who now keep alive people who, not very long ago, would have died of a variety of then incurable diseases. Through a wide variety of technological innovations that include farming methods and the control of deadly diseases, we have found ways to reduce the rate at which we die. However, this success is the very cause of the greatest threat to mankind.
If we examine the amount of land available for this ever-increasing population, we begin to see the problem. If everyone on the planet had an equal share of land, we would each have about:50,000 square meters. This figure seems to be quite encouraging until we examine the amount of usable land we actually have. More than three-fifths of the world&39;s land cannot produce food.
Obviously, with so little land to support us, we should be taking great care not to reduce it further. But we are not! Instead, we are consuming its "capital" -- its nonrenewable fossil fuels and other mineral deposits that took millions of years to form. but which are now being destroyed in decades. We are also doing the same with other vital resources not usually thought of as being nonrenewable such as fertile soils, groundwater and the millions of other species that share the earth with us.
It is a very common belief that the problems of the population explosion are caused mainly by poor people living in poor countries who do not know enough to limit their reproduction. This is not true. The actual number of people in an area is not as important as the effect they have on nature. Developing countries do have an effec.t on their environment, but it is the populations of richer countries that have a far greater impact on the earth as a whole.
According to the article， what contributes to the population increase？ 查看材料
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Don"t Rely on Plankton to Save the Planet
Encouraging plankton growth in the ocean has been touted by some as a promising way to remove carbon dioxide from the atmosphere. __________ (46)
Adding iron to patches of ocean can make plankton bloom temporarily. The microscopic organisms suck up dissolved carbon dioxide from the water, which in turn is replaced by carbon dioxide from the air. __________ (47)
Jorge Sarmiento from Princeton and his colleagues developed a complex computer model to analyze how factors such as ocean chemistry and water circulation would affect the process if 160,000square kilometers of ocean were seeded with iron for a month. __________ (48)
In their scenario, which covers an area 10 times as big as the largest experiment of this kind ever proposed, fertilizing the ocean removes 1 million tons of carbon from the atmosphere -- just 0.2 per cent of the carbon dioxide humankind spews out each month.
Rough estimates in the past have predicted similarly disappointing results. __________ (49) says Sallie Chisholm, an environmental engineer from the Massachusetts Institute of Technology.
"But the take-home message is the same. __________ (50)"
第46题___________ 查看材料
A 白细胞计数增多，主要为中性中幼粒细胞、晚幼粒细胞和杆状粒细胞
B 原始细胞＜10%，嗜酸和嗜碱粒细胞增多，可有少量幼红细胞
C CFU-GM培养集落和集簇较正常明显增加
D 骨髓增生活跃，以红系为主
A 糖化血红蛋白＜6.5%
B 餐后2小时血糖＜8.0毫摩尔/升
C 空腹血糖＜6.1毫摩尔/升
D 餐后2小时血糖＜6.5毫摩尔/升
[说明]
该程序从正文文件test.txt中读入一批整数，并将它们按照递增的顺序存放在一个链表中。其中，函数struct Link*insertChain(struct Link*head,structLink*k)用来寻找结点k在链表head中的插入位置，并插入该结点。
[C程序]
include ＜stdio.h＞
include ＜stdlib.h＞
struct Link
{ int number;
struct Link *next;
}
struct Link *insertChain(struct Link *head,struct Link *k);
VOid main()
{ struct Link *ptr, *head;
FILE *fd;
int hum;
if((fd=fopen("test.txt","r"))==NULL)
{print("Cannot open this file!\n");
return;
}
head=NULL；
while(fscanf(fd，"%d",hum)==1)
{ ptr=(1);
if(!ptr) return;
ptr-＞number=hum;
ptr-＞next=NULL;
head=insertChain(head，ptr);
}
(2);
return;
}
struct Link *insertChain(struct Link *head,struct Link *k)
{ struct Link *ptr,*u;
ptr=head;
while(ptr ＆＆ k ＆＆ k-＞number＞ptr-＞number)
{ u=ptr; (3) }
if(ptr == head) head=k;
else (4);
(5);
return head;
}
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