In the following question the first and the last parts of a short factual passage are numbered 1 and 6. The remaining parts P, Q, R and S are jumbled. The passage describes how settlers reached Alaska and how the Iditarod trail developed. Read the passage and choose the option that gives the correct sequence of P, Q, R and S.

Introduction / Context:
This rearrangement question is based on a descriptive passage about the early settlers in Alaska and the development of the Iditarod trail. The first sentence presents settlers coming to Alaska for gold, and the last sentence mentions that in winter the only means of travel down this trail is by dog sledge. You must order the middle sentences so that the history of the trail unfolds logically.

Given Data / Assumptions:

• Sentence 1 states that in the early nineteen twenties, settlers came to Alaska looking for gold.
• Part R explains that they travelled by boat to Seward and Krik and from there by land into the gold fields.
• Part Q tells us that the trail they used to travel inland is known today as the Iditarod trail.
• Part S says that this Iditarod trail quickly became a major thoroughfare in Alaska.
• Part P states that today people use it to get from place to place.
• Sentence 6 concludes that in winter the only means of travel down this trail is by dog sledge.

Concept / Approach:
The passage follows a clear historical order: first movement of settlers, then the path they created, then its importance, and finally its present use. We start with how they travelled, then name the trail, then describe its importance, and finally connect it to present travel conditions before the special note about winter travel in sentence 6.

Step-by-Step Solution:
Step 1: After sentence 1 tells us that settlers came to Alaska for gold, we expect information about the route they took. Part R describes their travel by boat and then by land into the gold fields, so R clearly comes next. Step 2: Once that route is described, the passage can name it. Part Q does this by stating that the trail they used is now known as the Iditarod trail. Step 3: Part S then logically explains that this trail quickly became a major thoroughfare, which shows its growing significance in Alaska. Step 4: After the historical importance is established, part P brings the description to the present day by saying that people still use the trail to get from place to place. This leads smoothly into sentence 6 about winter travel by dog sledge.

Verification / Alternative check:
Reading the sequence 1 R Q S P 6 presents a clear timeline: settlers arrive, they use a particular route, that route becomes the Iditarod trail, it becomes important, and people still use it today, with dog sledge as the only means in winter. The narrative moves naturally from past to present, with each sentence explaining or extending the previous one.

Why Other Options Are Wrong:
In PSQR, present day use (P) appears before the naming and historical development of the trail, which disrupts the time order. In PQRS, again the logical movement from past travel to naming and importance is broken. In QRSP, the name of the trail appears before any description of how settlers travelled, leaving the reader wondering how the trail originated.

Common Pitfalls:
Students often pay less attention to time markers like “today” and historical references like “in the early nineteen twenties”. Failing to order sentences according to timeline leads to a confusing paragraph. Always try to reconstruct the story: first what happened, then how it got its name, then how it developed, then what the situation is now.

Final Answer:
The correct order of the parts is R Q S P, so the correct option is RQSP.