文勇阅读两个小问题。望高人进来看一眼。谢谢了！

Candy_TsiaUID: 2621915

The Long-Term Stability of Ecosystems
Paragraph 2: An ecologist who studies a pond today may well find it relatively unchanged in a year’s time. Individual fish may be replaced, but the number of fish will tend to be the same from one year to the next. We can say that the properties of an ecosystem are more stable than the individual organisms that compose the ecosystem.

3. According to paragraph 2, which of the following principles of ecosystems can be learned by studying a pond?
○Ecosystem properties change more slowly than individuals in the system.
○The stability of an ecosystem tends to change as individuals are replaced.
○Individual organisms are stable from one year to the next.
○A change in the members of an organism does not affect an ecosystem’s properties
我选对了D。但想知道A错在哪里？

Paragraph 5: Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in mid-successional stages, not in the climax community. Once a redwood forest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more complicated system is, in general, more likely than a simple system to break down. (A fifteen-speed racing bicycle is more likely to break down than a child’s tricycle.)

7. Which of the following can be inferred from paragraph 5 about redwood forests?
○They become less stable as they mature.
○They support many species when they reach climax.
○They are found in temperate zones.
○They have reduced diversity during mid-successional stages.
B错在哪里？

水晶小鱼UID: 2471655

我在这里给你答案：https://bbs.gter.net/viewthre ... 19780&page=6&extra=

57，58楼

以后可以去阁子里问~~

Candy_TsiaUID: 2621915

2# 水晶小鱼

好的。谢谢你啊！人真好！
不过，为什么~~这个链接打不开的

水晶小鱼UID: 2471655

3# Candy_Tsia

那你点我签名档里面的，是一样的