2. The phrase “paved the way for” in the passage is closest in meaning to

  • A. come together with
  • B. made possible
  • C. increased the intensity of
  • D. made absolutely certain

3. Paragraph 2 suggests that the warming of the Alaskan climate affected bark beetles in which of the following ways 

  • A. By making it possible for a beetle to deposit its eggs in a greater number of trees
  • B. By making it possible for beetles to survive in the bark of trees for longer lengths of time
  • C. By making it unnecessary for a beetle to protect its eggs by laying them between the bark and the wood
  • D. By increasing the number of spruce trees, thereby providing the beetles with far more places to live

4. According to paragraph 2, all of the following contributed to the destruction of forests in different parts of the United States EXCEPT

  • A. a drought that had lasted for several years
  • B. a lack of forest management practices
  • C. overcrowding in forests
  • D. a huge increase in spruce tree pest populations

Paragraph 2

The biggest climate-caused ecosystem shifts today are happening at the world’s most northern latitudes, where the temperature over the last century has been rising about two times faster than the global average. In the northernmost state of the United States, Alaska, for example, warming has paved the way for a spike in the numbers of spruce bark beetles. Bark beetles have been a pest to Alaskan white spruce trees for thousands of years, but their numbers were held in check by the cold climate, which forced the insects to hide in the bark of individual trees for most of the year. As the length of the warm season increased over the 1980s and 1990s, however, bark beetles had more time to fly from one tree to the next, burrow, and lay their eggs between the bark and the wood. The beetles had another thing going for them, too: a multi-year drought had weakened many of the spruce trees, leaving them vulnerable to attack. In the mid-1990s, the bark beetle population exploded, and over the next few years the pests wiped out white spruce forests over an area the size of the U.S. state of Connecticut. In the years since, the combined forces of a longer insect-breeding season and forest management practices that left forests overcrowded gave way to similar epidemics farther south. Large swaths of pine and spruce have been destroyed by insects in several other parts of the United States.


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