Five jumbled sentences (labelled 1, 2, 3, 4, and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence out and key in the number of that sentence as your answer.
About half of all the oxygen we breathe is made near the surface of the ocean by phytoplankton that photosynthesize just like land-dwelling plants.
A team of scientists that includes Boston University experts has discovered they also produce oxygen on the seafloor.
The research team used deep-sea chambers that land on the seafloor and enclose the seawater, sediment, polymetallic nodules, and living organisms.
The discovery is a surprise considering oxygen is typically created by plants and organisms with help from the sun—not by rocks on the ocean floor.
The research team used deep-sea chambers that land on the seafloor and enclose the seawater, sediment, polymetallic nodules, and living organisms.
The correct answer is: "The research team used deep-sea chambers that land on the seafloor and enclose the seawater, sediment, polymetallic nodules, and living organisms."
Here is the step-by-step reasoning to understand why this sentence is the odd one out:
Step 1: Identify the central theme of the other sentences.
When we analyze the remaining sentences, they collectively form a coherent narrative about a new and surprising scientific discovery regarding oxygen production in the ocean. The primary focus of the paragraph is on the contrast between conventional knowledge of oxygen production and this unexpected new finding.
Step 2: Trace the logical flow of the coherent paragraph.
The coherent sentences connect logically to build this narrative:
- The paragraph sets the stage with established knowledge, explaining that about half of the oxygen we breathe is typically produced near the ocean's surface by photosynthesizing phytoplankton.
- It then introduces a contrasting breakthrough, stating that scientists have discovered oxygen is also being produced deep down on the seafloor.
- Finally, it highlights the significance and unexpected nature of this finding, noting that it is highly surprising because oxygen creation usually requires sunlight and living organisms, rather than "rocks on the ocean floor."
Step 3: Analyze the odd sentence out.
The chosen sentence discusses the specific equipment and experimental methodology the researchers used to make their discovery (using "deep-sea chambers" to enclose "seawater, sediment, polymetallic nodules, and living organisms"). While this sentence is tangentially related to the broader topic of the research, it is entirely focused on the technical procedure of the experiment. Including this detailed methodological description interrupts the conceptual flow of the other sentences, which are dedicated to explaining what the discovery is and why it matters, rather than the mechanical tools used to achieve it.
Therefore, because it abruptly shifts the scope from the discovery's broad implications to the procedural details of the experiment, it is the odd sentence out.