P: This fortuitous geological event generated a colossal amount of energy and heat that resulted in the rocks rising to an average height of 4 km across the contact zone.
Q: Thus, the geophysicists tend to think of the Himalayas as an active geological event rather than as a static geological feature.
R: The natural process of the cooling of this massive edifice absorbed large quantities of atmospheric carbon dioxide, altering the earth’s atmosphere and making it better suited for life.
S: Many millennia ago, a breakaway chunk of bedrock from the Antarctic Plate collided with the massive Eurasian Plate.
C
Step-by-Step Solution
Insight: The passage describes a geological sequence; the opening must introduce the event, followed by immediate effects, subsequent processes, and a concluding inference.
Exam route: Sentence S introduces the collision. Sentence P refers to "This... event", locking S→P. Sentence R discusses "cooling of this massive edifice", which must follow the "rocks rising" in P. Sentence Q starts with "Thus", making it the conclusion. Sequence SPRQ is the only match.
Learning route:
Step 1: Identify the opener. Sentence S introduces the specific historical event ("Many millennia ago... collided"). Sentences P, R, and Q contain dependent references ("This... event", "this massive edifice", "Thus") and cannot open the passage.
Step 2: Link cause and effect. Sentence P explicitly refers to "This fortuitous geological event", which must immediately follow the collision described in S. This forms the mandatory pair S→P.
Step 3: Follow the physical timeline. Sentence P describes the generation of heat and rocks rising. Sentence R describes the "cooling of this massive edifice". Cooling must chronologically follow the generation of heat and rising, forming the pair P→R.
Step 4: Identify the conclusion. Sentence Q begins with "Thus", signaling a summary or inference drawn from the preceding active geological processes, making it the natural closing sentence.
The sequence S→P→R→Q is logically and chronologically sound.