Question

Difficulty: MediumImplicit and Inferred Relationships

Passage:
For decades, oceanographers assumed the deep ocean floor was a biological desert, devoid of light and thus of life. This belief persisted until geophysicists noticed anomalous temperature spikes in the deep water of the Galapagos Rift. Seeking to map these thermal variations, researchers first deployed unmanned deep-tow camera sleds. The resulting photographs revealed unexpected clusters of giant clam shells littering the basaltic seabed, a finding that puzzled biologists who could not conceive of an energy source that could sustain them. Intrigued by these photographs, a team of scientists boarded the submersible Alvin to inspect the site firsthand. Descending into the abyss, they witnessed shimmering, superheated water billowing from chimney-like mineral structures. Surrounding these vents was a thriving, alien ecosystem of tubeworms and crabs. Only after collecting samples of the vent water did microbiologists identify the chemosynthetic bacteria that utilized hydrogen sulfide as an energy source, finally resolving how such a community could flourish in complete darkness.

Based on the passage, in what chronological order did these events occur, from earliest to latest?

  1. 1Oceanographers assuming the deep ocean floor was a biological desert.
  2. 2Geophysicists detecting unusual temperature patterns in the Galapagos Rift.
  3. 3Camera sleds capturing images of clam shells on the ocean floor.
  4. 4Researchers inside the submersible Alvin directly observing hydrothermal chimneys.
  5. 5Microbiologists identifying bacteria that convert chemical energy into food.

Answer

The chronological sequence of events is: oceanographers assuming the deep ocean floor was a biological desert, followed by geophysicists detecting unusual temperature patterns, then camera sleds capturing images of clam shells, then researchers inside the submersible Alvin directly observing hydrothermal chimneys, and finally microbiologists identifying bacteria that convert chemical energy into food.
The correct chronological sequence is established through logical progression and textual keywords. First, oceanographers assumed the deep ocean floor was barren. This belief ended when geophysicists noticed temperature spikes. Researchers then deployed camera sleds to map these spikes, which photographed clam shells. Intrigued by the photos, scientists descended in the Alvin to observe the vents. Finally, microbiologists analyzed the water samples collected during the dive to identify chemosynthetic bacteria.

Step-by-Step Solution

1
Identify the long-held scientific assumption that preceded the discoveries.
The oceanographers' assumption of a biological desert on the ocean floor is described as lasting 'for decades' before being challenged, placing it first.
This establishes the historical baseline before any anomalies were detected.
2
Determine the event that challenged the long-held assumption.
Geophysicists detected anomalous temperature spikes in the Galapagos Rift.
The text states the assumption 'persisted until' geophysicists noticed these temperature spikes, indicating this detection occurred next.
3
Identify the immediate research response to the temperature spikes.
Unmanned camera sleds were deployed to map the thermal variations and photographed clam shells.
The text explains that researchers deployed the camera sleds 'seeking to map these thermal variations' discovered by geophysicists.
4
Determine the manned mission that was prompted by the photographic evidence.
Scientists boarded the submersible Alvin and observed the hydrothermal chimneys firsthand.
The passage notes that the scientists were 'intrigued by these photographs' and subsequently boarded the Alvin.
5
Find the final analysis that resolved the biological mystery.
Microbiologists identified the chemosynthetic bacteria in the water samples.
The text specifies that 'only after collecting samples' (which occurred during the Alvin dive) did microbiologists identify the bacteria, placing this step last.

Key Concept

Analyzing implicit chronological sequences and cause-and-effect relationships using narrative transitions and logical prerequisites.
Estimated Time:1m 30s
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