Reading comp PrepTest 109 · Section 2 · Question 18

Topic: Science

Paragraph 1

• Paragraph note
  • Some researchers' argument (more CO2 in the atmosphere will increase vegetation and slow global warming)
• Views, minor Meta-Structures, and the author's attitude
  • Experts' view:
    • The amount of CO2 in the atmosphere will double by the end of the century (first sentence)
  • Cause-and-effect relationship, according to experts:
    • CO2 can cause global warming by trapping solar energy (second sentence)
  • Some researchers' view:
    • More CO2 will cause a chain reaction that actually fights the effects of global warming (third sentence)
  • Cause-and-effect relationship, according to some researchers:
    • More CO2 will cause more plants, which will cause more absorption of CO2, which will cause a lower increase of CO2 than predicted (third through last sentences)
  • Author's attitude: "is known" (second sentence)

Paragraph 2

• Paragraph note
  • Studies show more CO2 won't increase vegetation (more CO2 reduces crops, reduces stability, and increases fires)
• Views, minor Meta-Structures, and the author's attitude
  • Cause-and-effect relationships, according to studies:
    • More CO2 would cause some plants to outcompete others, which could cause a reduction in some important crops like corn and sugar cane (first and second sentences)
    • More CO2 could also cause an increase in certain weeds, which could cause ecosystem instability or more severe wildfires (third through last sentences)
  • Author's attitude: "However" (first sentence), "important crops" (second sentence), "may lead to" (last sentence), "more severe" (last sentence)

Paragraph 3

• Paragraph note
  • Billings' study shows more CO2 won't slow global warming (more plants won't offset increased decomposition)
• Views, minor Meta-Structures, and the author's attitude
  • Cause-and-effect relationship, according to Billings:
    • In wet tundra grasslands, increased temperatures will cause more CO2, which will cause increased plant growth, which causes more peat (dead plant material) to decompose, which causes a significant increase in CO2 that the increased plant growth can't offset (third through eighth sentences)
  • Author's view:
    • Billings' study is important because the tundra will experience the greatest temperature increase from global warming (last sentence)
  • Author's attitude: "It is clear" (first sentence), "does not guarantee" (first sentence) "particularly important" (last sentence)

Main Point: Studies suggest elevated CO2 levels will not guarantee lush agriculture or reduce global warming.

Correcting the Record: This passage utilizes a Correcting the Record Meta-Structure.* In a Correcting the Record passage, the author will describe a common misconception or false belief. Often, this belief is based on a lack of information. The author then explains why the beliefs are false.

That's precisely how this passage progresses. The author introduces the belief that expected increases of CO2 in the atmosphere could make the world agriculturally lush and even decrease the rate of global warming. The author then corrects both of those points with new studies. According to these studies, increased CO2 will not make the world agriculturally lush (because some plants will increase more than others, reducing ecological stability and increasing the prevalence of wildfires) or slow global warming (because it will increase decomposition and release even more CO2).

In passages that use a Correcting the Record Meta-Structure, the main point will generally summarize the author's explanation of why the misconception is false or just an assertion that the misconceptions are false. We kept it simple with our summary: "Studies suggest elevated CO2 levels will not guarantee lush agriculture or reduce global warming."

Cause and effect: The most prominent minor Meta-Structure is cause and effect. This isn't surprising, as this minor Meta-Structure is prevalent in science passages. Each paragraph asserts a cause-and-effect relationship. Having these noted or highlighted will help you answer the inevitable questions about these relationships.

There's no way around it: this is a dense, science-y passage. It's made a lot more tolerable, however, by realizing that the passage's arguments are causal arguments. The author and all the researchers mentioned — they are all making arguments about certain causes leading to certain effects. The hypothesis in the first sentence says that more CO2 will cause a decrease in the rate of global warming. The author says that CO2 will really just cause agricultural issues and the release of even more CO2. If you can, try committing these relationships to memory! It'll save you a lot of time and headaches as you answer the questions!