黃金閱讀 The Long-Term Stability of Ecosystems - 英檢

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 chang as individuals are replaced.
○Individual organisms are stable from one year to the next.
○A chang in the members of an organism does not affect an ecosystem's
properties.

寫的時候第選項1跟選項4讓我好掙扎
因為從段落裡來看選項1好像也頗有道理(因為最後一句話,we can say that....)
難道一開始說的relatively unchanged就代表完全不影響嗎?
有點疑惑難道全部的魚的數量不變，生態的properties就不變嗎??
想請問各位這題怎麼判斷才好

謝謝^^

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