Understanding the Sentence Ordering Task

This question requires us to arrange four jumbled sentences (P, Q, R, S) into a logical sequence between a fixed starting sentence (S1) and a fixed ending sentence (S6). The goal is to create a coherent paragraph that discusses the evidence for past climate change found in rocks and deposits.

Analyzing the Sentences

• S1: The primary evidence for climate change that occurred many million years ago is the rocks and deposits themselves. (Introduces the topic: geological evidence for past climate change.)
• S6: In other words, despite the clear legacy in many parts of the world of recent glaciation, the vast majority of sedimentary rocks were laid down in warm climatic conditions. (Provides a concluding summary, contrasting recent glaciation with long-term warm conditions.)
• P: Sediments and fossil in the poles tell us a great deal about the environment in which they were laid down. (Focuses on specific evidence - sediments and fossils - found in polar regions and what they indicate.)
• Q: We must, of course, bear in mind when interpreting this information that, because of the movement of the continents, no one latitude of the Earth has necessarily gone through such marked climatic vicissitudes. (Presents a crucial caveat for interpreting the evidence – continental drift affects our understanding of past climate zones.)
• R: Nevertheless, even allowing for this factor, one of the most remarkable discoveries about the climate change of the past is that the two poles of the Earth have been free of ice for at least 90 per cent of the known history of the planet. (Starts with "Nevertheless," indicating a contrast or significant point following previous considerations. It presents a major finding about the poles being largely ice-free.)
• S: We may find in close proximity to one another, coal deposits indicating the humid conditions of the tropics, red sandstones laid down in deserts and morainic materials reflecting polar conditions. (Gives concrete examples of diverse geological deposits found together, representing different climate zones.)

Constructing the Logical Flow (QSPR)

Let's determine the correct order by seeing how the sentences connect logically:

1. S1: Starts the passage by stating that rocks and deposits are the primary evidence for past climate change.
2. Q: Follows S1 by introducing a necessary caution: when interpreting this geological evidence, we must consider continental drift. This affects how we understand past climate variations (vicissitudes) at different latitudes. It prepares us for a more nuanced discussion.
3. S: Provides specific examples of the diverse geological deposits mentioned in S1. It illustrates how different climate indicators (coal for tropics, sandstones for deserts, morainic materials for polar conditions) can be found together, showcasing the variety of evidence.
4. P: Narrows the focus to evidence from specific locations. It elaborates on the 'polar conditions' mentioned in S by stating that sediments and fossils found in the poles reveal information about their past environments.
5. R: Begins with "Nevertheless," linking back to the complexities and factors discussed in Q. It contrasts the potential for varied climate signals with a significant finding: the poles have largely been ice-free for most of Earth's history. This adds a major piece of information about long-term climate patterns.
6. S6: Concludes the passage. It uses "In other words" to summarize the main point, contrasting the recent evidence of glaciation with the long-term stability of warm conditions, which aligns perfectly with the discovery presented in R.

Therefore, the correct order is QSPR.

Final Passage Structure

The sequence S1 - Q - S - P - R - S6 forms a coherent and logical passage:

S1: The primary evidence for climate change that occurred many million years ago is the rocks and deposits themselves. Q: We must, of course, bear in mind when interpreting this information that, because of the movement of the continents, no one latitude of the Earth has necessarily gone through such marked climatic vicissitudes. S: We may find in close proximity to one another, coal deposits indicating the humid conditions of the tropics, red sandstones laid down in deserts and morainic materials reflecting polar conditions. P: Sediments and fossil in the poles tell us a great deal about the environment in which they were laid down. R: Nevertheless, even allowing for this factor, one of the most remarkable discoveries about the climate change of the past is that the two poles of the Earth have been free of ice for at least 90 per cent of the known history of the planet. S6: In other words, despite the clear legacy in many parts of the world of recent glaciation, the vast majority of sedimentary rocks were laid down in warm climatic conditions.