Source: Official Guide Revised GRE 1st Ed. Part 8; Section 4; #6

3

It can be inferred that the author of the

It can be inferred that the author of the passage mentions predators (line 10) primarily in order to When marine organisms called phytoplankton photosynthesize, they absorb carbon dioxide dissolved in seawater, potentially causing a reduction in the concentration of atmospheric carbon dioxide, a gas that contributes to global warming. However, phytoplankton line flourish only in surface waters where iron levels are sufficiently high. Martin 5 therefore hypothesized that adding iron to iron-poor regions of the ocean could help alleviate global warming. While experiments subsequently confirmed that such a procedure increases phytoplankton growth, field tests have shown that such growth does not significantly lower atmospheric carbon dioxide. When phytoplankton utilize carbon dioxide for photosynthesis, the carbon becomes a building block for organic 10 matter, but the carbon leaks back into the atmosphere when predators consume the phytoplankton and respire carbon dioxide. help explain why Martin’s hypothesis is incorrect, identify one effect of adding iron to iron-poor waters, indicate how some carbon dioxide is converted to solid organic matter, help account for differences in the density of phytoplankton between different regions of the ocean, point out a factor that was not anticipated by the scientists who conducted the field tests mentioned in the passage

2 Explanations

4

Gravatar Cydney Seigerman, Magoosh Tutor

Hi Jae Sung :)

Choice E states: "point out a factor that was not anticipated by the scientists who conducted the field tests mentioned in the passage."

The key here is that we need to be able to infer the statement based on the passage. It is possible that the scientists did not anticipate that factor when they conducted the experiment. However, it's also possible that they did. We do not know based on the passage whether the scientists expected this observation or not. For that reason, we cannot infer E from the passage. On the other hand, the consequences of the predators' actions do contribute to the explanation as to why Martin's hypothesis was wrong.

I hope this helps! :)

May 18, 2016 • Comment

1

Gravatar Chris Lele, Magoosh Tutor

Oct 10, 2012 • Comment

Jae Sung Kim

For Question 6, can't it be answer choice E?

May 7, 2016 • Reply

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