The question below consists of a set of labelled sentence parts. Out of the four options given, select the most logical order of the parts X, Y and Z so that they form a coherent sentence. Another major difference X - seven planets around the star Y - system is the tight packing of the Z - in comparison with the solar.

Introduction / Context:
This is another sentence reordering question involving three labelled segments X, Y, and Z. The sentence discusses a planetary system and compares it with the solar system. The learner has to arrange the segments so that the sentence becomes grammatically correct and logically clear. Such questions test understanding of syntax, logical connections, and topic focus within complex sentences.

Given Data / Assumptions:
- Introductory part: “Another major difference”- Segment X: “seven planets around the star”- Segment Y: “system is the tight packing of the”- Segment Z: “in comparison with the solar”- The final sentence should compare one planetary system with the solar system in terms of how tightly its planets are packed.

Concept / Approach:
The structure we expect is something like: “Another major difference in comparison with the solar system is the tight packing of the seven planets around the star.” The phrase “in comparison with the solar system” should naturally come after “Another major difference,” because we want to say what we are comparing. Then we need the verb phrase “is the tight packing of the,” and finally we specify what is packed tightly, namely “seven planets around the star.” Thus, Z should come first after the initial phrase, followed by Y, then X.

Step-by-Step Solution:
Start with the given beginning: “Another major difference.” We now ask, “difference with respect to what?” Segment Z, “in comparison with the solar,” completes this idea by introducing “the solar system.” The preposition “in comparison with” fits directly after “difference.”Combining the start with Z, we get: “Another major difference in comparison with the solar ...” It is understood that “solar” here refers to the solar system.Next, we want a verb and a complement to state what this difference actually is. Segment Y reads “system is the tight packing of the,” and when placed after Z it becomes “solar system is the tight packing of the ...” This is grammatically correct and gives us the core clause: “the solar system is the tight packing of the ...”Finally, segment X, “seven planets around the star,” specifies what is being tightly packed. Joining X after Y yields: “the tight packing of the seven planets around the star.”Putting everything together, the complete sentence becomes: “Another major difference in comparison with the solar system is the tight packing of the seven planets around the star.” The sequence of labels is Z Y X.

Verification / Alternative check:
Check if any other order leads to a correct sentence. If we start with Y after “Another major difference,” we get “Another major difference system is the tight packing of the,” which is ungrammatical because “difference system” does not connect properly. If we start with X, we get “Another major difference seven planets around the star,” which lacks a preposition and does not make sense. Only Z provides the necessary comparative structure “in comparison with the solar system.” After Z, putting X before Y would give “in comparison with the solar seven planets around the star system is the tight packing of the,” which is obviously incorrect. Thus, ZYX is the only workable order.

Why Other Options Are Wrong:
Option ZXY misplaces the verb phrase and breaks the noun phrase “the tight packing of the seven planets around the star.”Option YZX starts with “system is the tight packing of the” immediately after “Another major difference,” which lacks a clear subject for “difference” and distorts the intended comparison.Option YXZ produces an even more confusing structure and fails to form a meaningful sentence.

Common Pitfalls:
Some learners may try to arrange the parts by intuition rather than checking grammatical roles. It is crucial to identify which segment introduces the comparison, which contains the main verb “is,” and which specifies the object being described. Noticing that Z begins with the comparative phrase “in comparison with,” and that Y contains “system is,” provides strong guidance for the correct arrangement.

Final Answer:
The most logical and grammatically correct order of the parts is ZYX.