When Marine Organisms Called Phytoplankton Photosynthesize, They Absorb Carbon Dioxide Dissolved in Seawater

Reading Passage Question

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 flourish only in surface waters where iron levels are sufficiently high. Martin 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 matter, but the carbon leaks back into the atmosphere when predators consume the phytoplankton and respire carbon dioxide.

“When marine organisms called phytoplankton photosynthesize, they absorb carbon dioxide” - is a GMAT reading comprehension passage with answers. Candidates need a strong knowledge of English GMAT reading comprehension.
This GMAT Reading Comprehension consists of 2 comprehension questions. The GMAT Reading Comprehension questions are designed for the purpose of testing candidates’ abilities in understanding, analyzing, and applying information or concepts. Candidates can actively prepare with the help of GMAT Reading Comprehension Practice Questions.

Solution and Explanation

1. It can be inferred from the passage that Martin’s hypothesis includes which of PRE the following elements?

1. A correct understanding of how phytoplankton photosynthesis utilizes carbon dioxide
2. A correct prediction about how the addition of iron to iron-poor waters would affect phytoplankton growth
3. An incorrect prediction about how phytoplankton growth would affect the concentration of atmospheric carbon dioxide

1. I only
2. II only
3. I and II only
4. I and III only
5. I, II, and III

2. It can be inferred that the author of the passage mentions predators (Highlighted) primarily in order to

1. help explain why Martin’s hypothesis is incorrect
2. identify one effect of adding iron to iron-poor waters
3. indicate how some carbon dioxide is converted to solid organic matter
4. help account for differences in the density of phytoplankton between different regions of the ocean
5. point out a factor that was not anticipated by the scientists who conducted the field tests mentioned in the passage

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