Practice Questions

Read the given passage and answer the following question.

(1) One of the greatest concerns of landscapers is tree disease.  Ash trees are among the most common trees in North America, and they are also very susceptible to disease and decline.

(2) One cause of decline in ash trees is ash yellows. This disease infects mainly white and green ash in the Northern United States. Ash yellows is caused by a phytoplasma: virus-like pathogens that are spread by insects. Ash yellows leads to a gradual decline 10 in tree health for about two to ten years before the tree dies. Some common symptoms include short inter-nodes and tufting of foliage at branch ends, pale green or pale yellow leaves, defoliation, and a sparse canopy. Cankers may also form on the branches and trunk. Unsightly “witches’ broom” sprouts might appear on the branches, but it is more common for them to appear on the trunk. The trunk may also develop cracks if the tree is infected with ash yellows. Rarely does an ash tree recover from ash yellows. Experts guess that this disease is more common than most home owners realize because witches’ brooms and yellowing are not always visible on the infected trees. Sometimes cankers and cracks are the only signs of the disease.

(3) The term ash decline is used to refer to a tree with more than one condition. Ash decline may involve the ash yellows disease or another problem called verticillium wilt. Ash decline is often used to describe any decline in health that is unexplainable. Ash decline involves branch tip death, defoliation, and a slow decline over a number of years. Trees with ash decline may appear to recover in the spring and decline again in July and August.

(4) Verticillium wilt on ash can also result in cankers and dieback similar to ash yellows. Trying to diagnose a tree is difficult because symptoms could be caused by a variety of problems. Sick ash trees may suffer from verticillium wilt, ash yellows, environmental stress, or a combination of these ailments.

(5) Ash yellows has been a known disease in the United States since the 1930s. However, the disease was not distinguished from general ash decline involving environmental factors until the 1980s. In the last eighty years, North America has seen a significant decline in some of its ash trees.

(6) No single factor has been proven to cause ash decline. Ash yellows and environmental factors may work together to create ash decline. Studies show that ash yellows is often detected where environmental factors like water shortage or insect damage are present. A survey of several Midwestern states found that some ash decline was found to be independent of ash yellows. The droughts in the 1980s may have caused the decline of ash trees in the Midwest. Cold winter temperatures may also play a role in decline.

(7) Ash trees are important in the ecology of NorthAmerican forests. The decline of these trees may have a severe impact on the health of other plant and animal communities. Green ash provides nesting sites for several species of birds and other wild creatures. Insects and fish flourish in the cool waters made possible by the shade of ash trees. Green and white ash are also very popular in landscaping. Their decline could result in reduced property values.

(8) Ash trees also represent a valuable hardwood resource. An estimated 275 million feet of ash lumber is harvested annually. In the Northeastern UnitedStates, about 33 percent of the commercial forest area includes ash trees.

(9) There are no known cures for the diseases mentioned. Experts recommend removing very sick trees while keeping healthy trees well watered and fertilized. Dead limbs should also be removed to maintain the health of ash trees.

According to the passage, many scientists feel that most ash decline is likely caused:

VIEW ANSWER
Answer: (B) by a combination of disease and environmental factors.

Explanation

The passage states, “No single factor has been proven to cause ash decline. Ash yellows and environmental factors may work together to create ash decline.” This best supports answer choice B.

The passage likens verticillium wilt to ash yellows in that:

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Answer: (F) both diseases share the symptoms of cankers and dieback.

Explanation

The passage states, “Verticillium wilt on ash can also result in cankers and dieback similar to ash yellows.” The other answer choices are not supported by the passage.

The difficulty in diagnosing disease in an ash tree is due to all of the following EXCEPT:

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Answer: (D) sick ash trees are difficult to test because they decline so rapidly.

Explanation

The passage gives the following reasons why it is hard to diagnose as ash tree:

  • Trying to diagnose a tree is difficult because symptoms could be caused by a variety of problems.
  • Ash yellows and environmental factors may work together to create ash decline.
  • A survey of several Midwestern states found that some ash decline was found to be independent of ash yellows.
  • Verticillium wilt on ash can also result in cankers and dieback similar to ash yellows.
  • The passage indicates that the trees may decline slowly, not rapidly.

The passage states that ash yellows is caused by:

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Answer: (G) virus-like pathogens.

Explanation

The passage states, “Ash yellows is caused by a phytoplasma: virus-like pathogens that are spread by insects.”

According to the passage, the author believes that:

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Answer: (C) ash trees are important because they can provide a home for some wildlife.

Explanation

The passage states, “The decline of these trees may have a severe impact on the health of other plant and animal communities. Green ash provides nesting sites for several species of birds and other wild creatures. Insects and fish flourish in the cool waters made possible by the shade of ash trees.” This best supports answer choice C.

According to the passage, which of the following is an argument for NOT blaming ash decline solely on ash yellows?

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Answer: (H) A study mentioned in the passage shows that drought and weather may contribute to ash decline.

Explanation

The passage states, “A survey of several Midwestern states found that some ash decline was found to be independent of ash yellows. The droughts in the 1980s may have caused the decline of ash trees in the Midwest.” The other answer choices are not supported by the passage.

As it is used in paragraph 7, the word flourish most nearly means:

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Answer: (B) prosper

Explanation

The passage states that, “Insects and fish flourish in the cool waters made possible by the shade of ash trees.” The paragraph discusses the importance of ash trees “in the ecology of North American forests.” It makes the most sense, based on the context of the paragraph, that “flourish” means “prosper.”

The author would most likely agree with which of the following statements?

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Answer: (F) It is important for research to continue into a cure for ash yellows.

Explanation

Throughout the passage the author states that ash trees are important and necessary. It makes sense that the author would agree with a statement suggesting that a cure for a disease that kills ash trees be researched. The other answer choices are not supported by the passage.

According to the passage, what is NOT a characteristic of the disease ash yellows?

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Answer: (D) It turns the leaves of ash trees bright yellow.

Explanation

The passage states that ash yellows turns the leaves of ash trees “pale green and pale yellow,” not bright yellow.

As it is used in paragraph 4, the word diagnose most nearly means:

VIEW ANSWER
Answer: (F) identify

Explanation

Diagnose: identify the nature of (an illness or other problem) by examination of the symptoms.

Example: "two doctors failed to diagnose a punctured lung"

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