The parts P, Q, R, and S of the following sentence have been jumbled. Choose the order that forms a coherent sentence: There is no reason P: that life may exist Q: in great profusion R: why we should not be willing to think S: in other worlds.

Introduction / Context:
This para jumble discusses the possibility of life existing elsewhere in the universe. The sentence must be arranged so that it forms a logical philosophical statement. Recognising the role of "why" in introducing a clause after "There is no reason" is crucial to putting the fragments in proper order.

Given Data / Assumptions:
The pieces are:
- P: that life may exist
- Q: in great profusion
- R: why we should not be willing to think
- S: in other worlds
The fixed beginning is "There is no reason".

Concept / Approach:
The phrase "There is no reason why" is a standard English pattern. So R "why we should not be willing to think" must follow the opening. This clause then needs a content clause introduced by "that", supplied by P "that life may exist". Additional adverbial phrases "in great profusion" and "in other worlds" then specify the extent and location of that life. Together, the natural order of ideas is: R P Q S.

Step-by-Step Solution:
Step 1: Combine the start with R: "There is no reason why we should not be willing to think". Step 2: Attach P: "that life may exist", which tells us what we are willing to think. Step 3: Add Q: "in great profusion", explaining that life might be present in large quantities. Step 4: Finish with S: "in other worlds", which tells us where this abundant life may exist. Step 5: The full sentence becomes "There is no reason why we should not be willing to think that life may exist in great profusion in other worlds."

Verification / Alternative check:
Match this with the options. The sequence R P Q S fits option C. If we try option A, R S P Q, we would get "why we should not be willing to think in other worlds that life may exist in great profusion", which misplaces the phrase "in other worlds". Option B, starting with P, fails to connect properly to "There is no reason", because "There is no reason that life may exist" is not the intended structure.

Why Other Options Are Wrong:
- "R S P Q": disrupts the natural link between "think" and the clause "that life may exist".
- "P Q S R": beginning directly with content and postponing "why we should not be willing to think" makes the sentence awkward and breaks the standard pattern "no reason why".
- "R Q S P": inserts adverbial phrases before the content clause "that life may exist", which leads to confusion about what exactly is being thought.

Common Pitfalls:
Many learners forget that "There is no reason why" is a fixed expression and try to start a sentence with "that life may exist" after "There is no reason". Always look for classic English patterns like "no reason why", "the fact that", or "it is believed that" as strong clues for sentence order. These often guide you to the correct initial combination of fragments.

Final Answer:
The correct sequence is R P Q S, giving a clear statement about the possibility of life in other worlds.