Question

Difficulty: HardEvaluating Whole-Essay Goals and Purpose

Deep-Sea Oasis

[1]
For generations, oceanographers operated under a fundamental assumption: all marine life ultimately depended on sunlight. Photosynthetic phytoplankton at the ocean's surface formed the base of the marine food web. It was believed that the abyssal plains, shrouded in perpetual darkness, could support only a sparse population of scavengers relying on "marine snow"—organic debris drifting down from above.

[2]
This view was shattered in 1977 during an expedition in the Pacific Ocean near the Galápagos Islands. Researchers aboard the submersible Alvin descended more than 2,500 meters to the ocean floor. Instead of a barren desert, they discovered hydrothermal vents spewing superheated, mineral-rich water. Surrounding these vents were dense, thriving ecosystems teeming with giant tube worms, blind crabs, and massive clams, all thriving in conditions previously thought to be completely uninhabitable.

[3]
The key to this thriving community was chemosynthesis, a process completely independent of sunlight. Specialized bacteria utilized the toxic hydrogen sulfide dissolved in the vent fluids to produce organic molecules, serving as the primary producers for this alien ecosystem. This discovery revolutionized our understanding of life's adaptability and opened new possibilities for where life might exist elsewhere in the universe.

Suppose the writer's goal had been to write an essay that describes how a major scientific discovery challenged a long-held biological assumption. Would this essay successfully fulfill that goal?

  1. Yes, because it explains how the discovery of hydrothermal vent ecosystems disproved the belief that all marine life relies on sunlight.Answer
  2. B
    Yes, because it details the engineering achievements of the submersible Alvin and its role in deep-sea mapping.
  3. C
    No, because the essay focuses primarily on the chemical structure of hydrogen sulfide rather than the biology of the vents.
  4. D
    No, because the essay fails to specify the year or location of the expedition that made the discovery.

Answer

Yes, because the essay explains how the discovery of hydrothermal vent ecosystems disproved the belief that all marine life relies on sunlight.
The correct answer is correct because the passage explicitly describes the previous biological assumption that all marine life depends on sunlight (Paragraph 1) and then explains how the discovery of hydrothermal vents driven by chemosynthesis disproved this assumption (Paragraphs 2 and 3).

Step-by-Step Solution

1
Identify the long-held biological assumption mentioned in the essay.
The first paragraph states that scientists assumed all marine life depended on sunlight.
To evaluate if the goal is met, we must determine if the essay contains the assumption mentioned in the goal.
2
Identify the scientific discovery and see if it challenged this assumption.
The second and third paragraphs describe the 1977 discovery of hydrothermal vents where life thrives via chemosynthesis, completely independent of sunlight.
We must verify if the discovery challenged the identified assumption.
3
Determine if the overall essay fulfills the writer's goal.
Yes, the essay describes the discovery and how it directly challenged the assumption that life requires sunlight.
This establishes the correct direction (Yes) and the matching reasoning.

Key Concept

Evaluating Whole-Essay Goals and Purpose
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