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Question

Difficulty: HardOpening and Concluding Sentences

A student is writing an essay about the 1977 discovery of deep-sea hydrothermal vents. Read the five sentences below and arrange them in the most logical order to create a cohesive paragraph that establishes a clear introduction and transitions smoothly to a strong conclusion.

  1. 1In 1977, oceanographers aboard the research submersible *Alvin* made a discovery off the Galápagos Islands that would fundamentally rewrite our understanding of life on Earth.
  2. 2They descended into the pitch-black depths of the Pacific Ocean, expecting to find a barren, lifeless volcanic seafloor.
  3. 3Instead, they encountered hydrothermal vents spewing superheated, mineral-rich water, surrounded by dense communities of bizarre creatures.
  4. 4These organisms, including giant tubeworms and ghost-like crabs, thrived not on sunlight, but on chemical energy through a process called chemosynthesis.
  5. 5This revelation proved that complex ecosystems could flourish completely independent of solar energy, expanding the possibilities for finding life on other planets.

Answer

The correct logical sequence begins with the introduction of the oceanographers' 1977 discovery, moves to the description of their descent, transitions to the unexpected finding of hydrothermal vents, explains the chemosynthetic nature of the organisms found, and concludes with the broader impact of this scientific revelation.
The paragraph begins with a clear introduction that establishes the historical and scientific context of the 1977 discovery. The second sentence flows logically by using the pronoun 'They' to refer back to the 'oceanographers' and describes their initial expectations. The third sentence uses the transitional word 'Instead' to introduce the actual, surprising discovery, directly countering those expectations. The fourth sentence builds on this discovery by detailing the 'bizarre creatures' as 'These organisms' and describing their survival method. Finally, the fifth sentence concludes the paragraph by highlighting the wider scientific implications of 'this revelation,' resolving the opening sentence's claim that the discovery would rewrite our understanding of life.

Step-by-Step Solution

1
Identify the introductory sentence that provides context and sets the topic.
The sentence introducing the 1977 discovery off the Galápagos Islands establishes the subject and main idea without relying on previous context.
An effective paragraph must begin with an independent opening sentence that defines the topic and outlines its significance.
2
Find the logical continuation of the introduction by tracking pronoun references.
The sentence beginning with 'They' immediately follows the introduction, as 'They' refers directly to the 'oceanographers'.
Cohesive writing requires that pronouns have clear, immediately preceding antecedents to prevent ambiguity.
3
Identify the sentence that transitions from expectations to the actual discovery.
The sentence starting with 'Instead' directly contrasts the expectation of a 'barren, lifeless' seafloor with the discovery of vents and creatures.
The transitional adverb 'Instead' marks a shift and must follow a sentence that sets up an expectation or state that is being contradicted.
4
Link details about the organisms to the sentence that introduced them.
The sentence explaining 'chemosynthesis' follows the sentence that introduced the 'dense communities of bizarre creatures', using the demonstrative phrase 'These organisms'.
The demonstrative adjective 'These' must refer back to a noun phrase in the immediate preceding context.
5
Select the sentence that summarizes the findings and offers a broader conclusion.
The sentence starting with 'This revelation' wraps up the paragraph by discussing the wider scientific implications for finding extraterrestrial life.
A concluding sentence should not introduce new narrow details but should synthesize the paragraph's points and return to the main theme of the introduction.

Key Concept

Developing paragraph unity and cohesion through logical sequencing, pronoun-antecedent tracking, transitional markers, and matching introductory and concluding scopes.
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Topics

Opening and Concluding Sentences

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