Scientists have discovered a remarkable undersea field of hot springs and gigantic chimneys, unlike anything seen before, and named it...
GMAT Reading Comprehension : (RC) Questions
Scientists have discovered a remarkable undersea field of hot springs and gigantic chimneys, unlike anything seen before, and named it Lost City. Geologist Deborah Kelley led an expedition to analyze Lost City, obtaining results that have prompted reconsideration of how life on Earth first emerged and of where extraterrestrial life might also exist.
Around most hydrothermal vents, the seawater is extremely acidic and reaches temperatures over 400 degrees Celsius. But at Lost City, the water is alkaline and no hotter than 90 degrees Celsius. And unlike other hydrothermal vents, those at Lost City are situated on seafloor consisting mainly of rock called peridotite. Seawater reacts with the peridotite, producing energy-rich gases such as hydrogen and methane.
Some scientists speculate that these gases could have fostered the emergence of life on Earth. A famous experiment conducted in 1952 showed that sparks discharging through energy-rich gases produce many organic compounds, including amino acids, which are components of all living things. However, geologists later concluded that these gases were probably not concentrated enough in Earth's early atmosphere to form such compounds. But the gases are far more concentrated in the Lost City waters.
Billions of years ago, could vents resembling those at Lost City have produced the organic compounds required for life? Hydrothermal fluids at Lost City contain certain organic compounds. And on early Earth, peridotite probably comprised most of the seafloor, making conditions like those at Lost City far more common than they are today.Lost City also teems with microbes such as methanogens, which metabolize hydrogen and generate methane. Each step in the geothermal process that generates methane is replicated in the biochemical pathways of these methanogens. This suggests that on early Earth, the methanogens' primordial ancestors at sites like Lost City may have simply co-opted each of the geochemical steps for themselves, producing the first biochemical pathways, which their descendents have inherited.
The Lost City findings also suggest that extraterrestrial life could exist on any planet or moon containing peridotite and liquid water. Evidence of these components is strongest on Mars and on Jupiter's moon Europa, and researchers have detected methane in the Martian atmosphere. Whether the methane comes from microbes or chemical reactions remains uncertain.
To support the hypothesis that hydrogen and methane fostered the emergence of life on Earth, the passage mentions the
1. Passage Analysis:
Progressive Passage Analysis
| Text from Passage | Analysis |
|---|---|
| Scientists have discovered a remarkable undersea field of hot springs and gigantic chimneys, unlike anything seen before, and named it Lost City. | What it says: Scientists found an unusual underwater area with hot water and tall structures called Lost City. What it does: Introduces the main subject - a unique underwater discovery Source/Type: Factual discovery announcement Connection to Previous Sentences: This is our opening - no prior context to connect to Visualization: Imagine discovering an underwater area the size of several football fields with tower-like structures 60 meters tall shooting hot water, completely different from typical ocean floor What We Know So Far: There's a unique underwater place called Lost City What We Don't Know Yet: What makes it special, why it matters, what scientists found there |
| Geologist Deborah Kelley led an expedition to analyze Lost City, obtaining results that have prompted reconsideration of how life on Earth first emerged and of where extraterrestrial life might also exist. | What it says: A scientist studied Lost City and found things that make us rethink how life started on Earth and where it might exist in space. What it does: Establishes the significance and introduces the main researcher Source/Type: Factual description of research impact Connection to Previous Sentences: This builds directly on sentence 1 by explaining WHY Lost City matters - it's not just unusual, it's revolutionary for understanding life Visualization: Scientists studying Lost City discovered evidence so important it's changing textbooks about how the first living things appeared 3.8 billion years ago AND where we might find alien life What We Know So Far: Lost City is unique and has major implications for understanding life's origins What We Don't Know Yet: What specific features make it special, what the actual discoveries were |
| Around most hydrothermal vents, the seawater is extremely acidic and reaches temperatures over 400 degrees Celsius. But at Lost City, the water is alkaline and no hotter than 90 degrees Celsius. | What it says: Unlike typical underwater vents that are very acidic and extremely hot (400°C), Lost City has basic water that's only moderately hot (90°C). What it does: Provides the first concrete difference that makes Lost City unique Source/Type: Scientific comparison/factual data Connection to Previous Sentences: This explains the "unlike anything seen before" claim from sentence 1 with specific evidence. The author is helping us understand what makes Lost City special. Visualization: Regular vents: Water hot enough to melt lead (400°C) and acidic like battery acid Lost City: Water temperature like a hot bath (90°C) and basic like baking soda solution Reading Strategy Insight: Feel confident here - the author is giving us concrete details to support earlier claims, not adding complexity |
Why It's Wrong:
- The passage actually states that gases were "probably not concentrated enough in Earth's early atmosphere" to form organic compounds
- This works against the hypothesis rather than supporting it
- The atmospheric concentration issue was presented as a problem that needed to be resolved, not as supporting evidence
Common Student Mistakes:
- Did you confuse the 1952 experiment's gas concentrations with early atmosphere concentrations?
→ The 1952 experiment used concentrated gases in lab conditions, but geologists concluded early Earth's atmosphere lacked sufficient concentration - Did you miss that this was presented as a contradiction to be resolved?
→ Look for the "However" that introduces this as a problem with the atmospheric theory
Why It's Wrong:
- While sparks are mentioned in the 1952 experiment, the passage doesn't mention sparks occurring around hydrothermal vents
- The passage discusses the 1952 lab experiment separately from the Lost City vent conditions
- This confuses laboratory conditions with natural vent environments
Common Student Mistakes:
- Did you conflate the 1952 laboratory experiment with Lost City conditions?
→ The experiment used artificial sparks in a lab; Lost City involves natural chemical reactions - Are you assuming the same mechanisms apply in both settings?
→ The passage presents these as separate pieces of evidence, not the same process
Why It's Right:
- The passage explicitly states this as crucial evidence: "on early Earth, peridotite probably comprised most of the seafloor, making conditions like those at Lost City far more common than they are today"
- This directly supports the hypothesis by showing that the gas-producing conditions existed widely on ancient Earth
- It resolves how local Lost City conditions could explain global life emergence
Key Evidence: "And on early Earth, peridotite probably comprised most of the seafloor, making conditions like those at Lost City far more common than they are today."
Why It's Wrong:
- The passage mentions Lost City's current temperature and alkalinity but doesn't discuss ancient Earth's seawater conditions
- Temperature and alkalinity are presented as distinguishing features of Lost City, not as evidence about early Earth
- This information describes current conditions at Lost City rather than supporting the ancient life hypothesis
Common Student Mistakes:
- Are you confusing current Lost City conditions with ancient Earth conditions?
→ The passage describes Lost City's unique temperature/alkalinity but doesn't claim ancient Earth had these same water conditions globally - Did you assume all Lost City features are mentioned as evidence for the life-origin hypothesis?
→ Some features distinguish Lost City from other vents, while others specifically support the ancient life theory
Why It's Wrong:
- While seawater reacting with peridotite to produce gases is mentioned, this describes the mechanism rather than supporting evidence for the hypothesis
- The passage presents this as how the gases are created, not as evidence that they fostered life emergence
- This is more about the chemical process than about supporting the life-origin theory
Common Student Mistakes:
- Are you confusing the mechanism of gas production with evidence for the life-origin hypothesis?
→ Explaining how gases form is different from providing evidence that these gases could create early life - Did you focus on the chemical reaction rather than the supporting argument?
→ Look for what makes this relevant to ancient Earth and life's emergence, not just current chemical processes