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Difficulty: Very hardRhetorical Synthesis: Summarization and Generalization

A student takes the following notes while researching the subterranean bacterium *Desulforudis audaxviator*:
* *Desulforudis audaxviator* is a rod-shaped bacterium found 2.82.8 kilometers below Earth's surface in a South African gold mine.
* It lives in absolute darkness and is completely cut off from the surface biosphere.
* Instead of using sunlight or consuming organic matter, it obtains energy from the radiolysis of water driven by the radioactive decay of surrounding minerals.
* It utilizes this energy to build its own organic compounds from inorganic carbon and nitrogen dissolved in its aquatic environment.
* It is the sole resident of its deep-subsurface habitat, representing a self-contained, single-species ecosystem.

The student wants to present a generalization about how *Desulforudis audaxviator* maintains ecological independence. Which choice most effectively uses information from the notes to accomplish this goal?

  1. A
    Discovered 2.82.8 kilometers below the surface in a South African gold mine, the rod-shaped bacterium *Desulforudis audaxviator* is the only species that lives in its dark, aquatic habitat.
  2. B
    Because it functions as a self-contained, single-species ecosystem, *Desulforudis audaxviator* serves as proof that complex multicellular life forms can thrive in deep-subsurface environments.
  3. Unlike typical organisms that depend on the solar-powered surface biosphere, *Desulforudis audaxviator* maintains complete ecological independence by using geothermal radioactivity to synthesize its own organic nutrients.Answer
  4. D
    By utilizing sunlight and organic matter transported from the surface biosphere, *Desulforudis audaxviator* obtains the hydrogen necessary to reduce sulfate and survive in absolute darkness.

Answer

The choice stating that *Desulforudis audaxviator* maintains complete ecological independence by using geothermal radioactivity rather than the solar-powered surface biosphere.
The correct option successfully presents a generalization about how the bacterium maintains ecological independence. It explains that the organism does not rely on the solar-powered surface biosphere (unlike typical organisms) and instead uses geothermal radioactivity to synthesize its own organic nutrients, directly matching the information in the notes to establish a broad generalization about its survival strategy.

Step-by-Step Solution

1
Analyze the student's rhetorical goal.
The goal is to present a generalization about how the bacterium maintains ecological independence.
This requires identifying a choice that summarizes the organism's energy generation and food synthesis mechanisms as a broad rule, contrasting it with typical surface life.
2
Evaluate the options against the provided notes.
The correct choice must capture both the lack of dependence on surface resources (sunlight/organic matter) and the alternative geological energy source (radioactive decay).
This distinguishes the correct generalization from options that focus on narrow details or introduce unsupported speculations.
3
Identify and eliminate incorrect distractors.
The option focusing on location details is too specific; the option mentioning multicellular life is unsupported; the option claiming it uses sunlight is factually incorrect.
This leaves only the correct option which accurately generalizes the ecological independence of the bacterium.

Key Concept

Rhetorical Synthesis: Summarization and Generalization
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Topics

Rhetorical Synthesis: Summarization and Generalization

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