问题 读图填空题

下图是某生态系统中部分生物构成的食物网,据图分析回答:

(1)图中共有食物链____条。

(2)图中生产者指________。

(3)图中B和A的关系是____________。

(4)除图中表示的成分外,生态系统的其他组成成分还有________和____________。

(5)若该生态系统被DDT污染,则含DDT最多的生物是________,原因是____________。

(6)图中最长的含生物C的食物链是____________________________。

(7)若F被大量捕杀,短期内数量增加的生物有________,生物G将____________。

答案

(1)4  

(2)A

(3)吃与被吃

(4)分解者     非生物环境

(5)G    DDT 随食物链不断富集

(6)A→B→C→F→G

(7)G、E     减少

选择题
填空题



Most taxpayers have had enough income tax collected by their employers during the year. So they do not (36) any money. In fact, most Americans get some money back. Last year, the Internal Revenue Service returned at least some money to more than (37) Americans paying individual income tax.
The United States has what is called (38) . Tax rates increase as (39) increase. This year, people earning more than (40) are taxed at the highest rate.
Earnings above that amount are taxed at (41) . Earnings below that amount are taxed at lower rates.
Individuals who earn less than (42) pay no income tax. But they do pay (43) , Medicare and other taxes.
There are many different ways for people and businesses to reduce their (44) Most homeowners, for example, can reduce their taxes a little by reporting to the I.R.S. the interest they pay (45) . This is called a (46)
In 2004, personal income taxes provided the government with most of its money: (47) of the budget. Social security and other (48) taxes provided (49) . Other forms of income include (50) , money borrowed to (51) and special taxes on (52) .
But income from taxes did not provide enough to pay for government spending. The I.R.S. says the budget deficit for 2004 was about (53) dollars.
Preparing tax documents can be complex. The I.R.S. estimates that taxpayers need an average of about 13 hours to prepare tax documents. And that is just for the basic tax form. For business, the I.R.S. estimates an (54) needs more than 50 hours. This is why a lot of Americans pay (55) to complete their tax documents for them.