7. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage Incorrect choices change the meaning in important ways or leave out essential information.
- A. Ecosystems like the spruce ecosystem in Alaska tend to return to their previous states after disturbances such as pest outbreaks, fires, or major storm events.
- B. While ecosystems tend to return to their previous states after disturbances, the Alaskan spruce ecosystem might not if it is disturbed too often or too much.
- C. Ecosystems tend to return to their previous states after disturbances, so Alaska might again become covered with woodlands or grasslands.
- D. After certain types of disturbances such as pest outbreaks, ecosystems do not always return to their previous states but shift to being woodlands or grasslands instead.
8. Look at the four squares that indicate where the following sentence could be added to the passage.
But even from this limited perspective, the answer is not completely straightforward.
Where would the sentence best fit Click on a square to add the sentence to the passage.
█Ecosystem changes always hurt some living creatures and help others. It’s hard to say, therefore, whether a change is good or bad overall. █Instead, ecologists (people who study ecosystems) often focus on the impacts on a single species: for instance, us. █ In the short term, the Alaskan spruce beetle epidemic supplied a lot of people with firewood, but only by destroying tons of otherwise valuable timber and threatening the livelihoods of loggers. █And no one knows for sure what the long-term impacts on the forest will be. Ecosystems tend to return to their previous states after disturbances like pest outbreaks, fires, or major storm events, but if the Alaskan spruce ecosystem is disturbed too often or too much, it might shift to a different type of forest, a woodland, or a grassland instead.