In the following item, a passage about the housefly is jumbled. The passage consists of six sentences with S1 and S6 fixed at the beginning and the end. The four middle sentences labelled P, Q, R and S are given in a mixed order. Read the passage carefully and choose the option that gives the correct sequence of P, Q, R and S between S1 and S6. S1: Do you not think that the housefly is a nuisance? S6: When you see a fly rubbing its legs together, it is just cleaning itself and scraping off some of the material that has gathered there. P: For ages that is what human beings considered the fly to be, just a nuisance. Q: It was later discovered that these flies carried disease germs that cause the death of millions of people every year. R: But now we know that the innocent looking housefly is one of humanity's worst enemies. S: It makes an irritating buzzing sound, it annoys you when it crawls on your skin, and so on. The proper sequence should be

Introduction / Context:
This jumbled passage discusses how people view the common housefly. It starts by asking whether the housefly is a nuisance and ends by explaining what it is doing when it rubs its legs together. The middle sentences must describe why people find it annoying, how they used to think of it, and what science has revealed about its danger as a carrier of disease.

Given Data / Assumptions:

• S1: Asks whether the housefly is a nuisance.
• S6: Explains that when a fly rubs its legs together, it is cleaning itself.
• S: Describes the nuisance aspects, such as the buzzing sound and crawling on skin.
• P: Says that for ages people considered the fly only a nuisance.
• R: Explains that now we know the housefly is actually one of humanity's worst enemies.
• Q: States that scientists discovered that flies carry deadly disease germs.
• We assume the passage moves from everyday annoyance to historical perception, then to scientific truth and finally to specific disease danger.

Concept / Approach:
To order these sentences:

• Begin with specific examples of the nuisance mentioned in S1.
• Then state the long held belief that the fly was only a nuisance.
• Next, introduce the contrast that now we know more serious facts.
• Finally, support that contrast by explaining the discovery about disease germs.

Look for contrast markers such as “But now we know” to identify turning points in the argument.

Step-by-Step Solution:
Step 1: After the question in S1, the passage should give concrete reasons why people think the fly is a nuisance. Sentence S provides these concrete examples: buzzing, crawling on skin and causing irritation, so S follows S1. Step 2: Once specific nuisances are listed, P summarises the traditional human view: “For ages that is what human beings considered the fly to be, just a nuisance.” This generalisation naturally follows the examples in S. Step 3: Then the passage must introduce a contrast between past and present understanding. Sentence R does this: “But now we know that the innocent looking housefly is one of humanity's worst enemies.” The word “But” signals a shift from the old view in P. Step 4: Finally, Q explains why it is one of our worst enemies: because it has been discovered that flies carry disease germs causing millions of deaths. This strengthens the claim made in R. Step 5: With S, P, R and Q inserted between S1 and S6, the argument flows smoothly from simple annoyance to deadly danger, before returning in S6 to a specific observable behaviour of the fly.

Verification / Alternative check:
Reading the passage in the order S1, S, P, R, Q and S6, you get a clear structure: first, reasons why people call the fly a nuisance; second, the traditional belief; third, the contrasting modern understanding; fourth, scientific evidence of the danger; and finally, an interesting fact about the fly cleaning itself. The logical contrast between “just a nuisance” and “worst enemy” is strong and well supported by Q, confirming that the sequence is correct.

Why Other Options Are Wrong:
R Q P S: This starts with the modern view that the fly is our enemy before explaining why people thought it was a nuisance, which breaks the natural flow from common experience to scientific understanding.
P Q S R: This order jumps from “just a nuisance” directly to carrying disease, then reverts to examples of buzzing and crawling, and finally announces that now we know better. This back and forth movement creates confusion.
Q P R S and similar orders detach the explanation about disease germs from the contrasting statement in R and fail to build the argument systematically from everyday experience to scientific fact.

Common Pitfalls:
A common error is to overlook signal words such as “But now we know” that clearly indicate a shift in the line of thought. Another pitfall is to treat each sentence as independent rather than part of a small argument. When you see examples followed by a general statement, then a contrast, and then supporting evidence, you should place them in that order to maintain coherence.

Final Answer:
The correct sequence is S P R Q, so the correct option is “S P R Q”.