Microbes that live in shallow lakes and ponds produce methane, a harmful greenhouse gas. Ecologist Ralf Aben and his team...
GMAT Information and Ideas : (Ideas) Questions
Microbes that live in shallow lakes and ponds produce methane, a harmful greenhouse gas. Ecologist Ralf Aben and his team wanted to see how different types of shallow-water plants might affect the amount of methane that escapes into the atmosphere. Aben's team set up some water tanks with soil and microbes from local ponds. Some tanks had a type of underwater plant that grows in the soil called watermilfoil. Other tanks had either duckweed, a type of plant that floats on the water's surface, or algae. Aben and his team found that tanks with duckweed and algae released higher levels of methane than tanks with watermilfoil did. This finding suggests that ______
Which choice most logically completes the text?
the presence of some kinds of underwater plants like watermilfoil helps prevent methane from escaping shallow lakes and ponds.
shallow lakes and ponds release more methane than deeper bodies of water because shallow bodies of water usually have more plants than deep bodies of water do.
shallow lakes and ponds are more likely to contain algae than to contain either watermilfoil or duckweed.
having a mix of algae, underwater plants, and floating plants is the best way to reduce the amount of methane in shallow lakes and ponds.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Microbes that live in shallow lakes and ponds produce methane, a harmful greenhouse gas." |
|
| "Ecologist Ralf Aben and his team wanted to see how different types of shallow-water plants might affect the amount of methane that escapes into the atmosphere." |
|
| "Aben's team set up some water tanks with soil and microbes from local ponds." |
|
| "Some tanks had a type of underwater plant that grows in the soil called watermilfoil." |
|
| "Other tanks had either duckweed, a type of plant that floats on the water's surface, or algae." |
|
| "Aben and his team found that tanks with duckweed and algae released higher levels of methane than tanks with watermilfoil did." |
|
Provide Passage Architecture & Core Elements
Main Point: An experiment showed that different types of plants in shallow water have different effects on methane release, with watermilfoil producing less methane than duckweed or algae.
Argument Flow: The passage establishes methane as an environmental problem from shallow water microbes, then describes a controlled experiment comparing different plant types' effects on methane release. The key finding shows watermilfoil tanks released less methane than tanks with duckweed or algae.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The key experimental result was clear: watermilfoil tanks released less methane than duckweed and algae tanks
- Since we're looking for what this "suggests," we need an inference that directly follows from this comparison
- The right answer should focus on the difference between watermilfoil and the other plant types and explain what the lower methane release from watermilfoil implies
the presence of some kinds of underwater plants like watermilfoil helps prevent methane from escaping shallow lakes and ponds.
- This directly matches our experimental finding - watermilfoil tanks had lower methane release
- The phrase "helps prevent methane from escaping" perfectly captures what lower methane levels would suggest
shallow lakes and ponds release more methane than deeper bodies of water because shallow bodies of water usually have more plants than deep bodies of water do.
- This compares shallow vs. deep water bodies, but our experiment only tested shallow water
- Makes claims not supported by the study
shallow lakes and ponds are more likely to contain algae than to contain either watermilfoil or duckweed.
- This is about which plants are more likely to be found where
- Our experiment doesn't tell us anything about the natural distribution of these plants
having a mix of algae, underwater plants, and floating plants is the best way to reduce the amount of methane in shallow lakes and ponds.
- Suggests mixing different plants is best, but the experiment showed watermilfoil alone performed better than the alternatives tested