Concept:Logical sequencing of sentences to form a coherent paragraph about equatorial precipitation.
Explanation:Sentence S1 introduces abundant precipitation in the equatorial zone.
Sentence R immediately follows, explaining that this high precipitation is due to high temperature, high humidity, and unstable air.
Sentence S then adds that trade winds from both hemispheres converge, causing upward motion of air.
Sentence P describes how ascending air currents intensify in tropical storms, producing abundant precipitation in specific regions.
Sentence Q explains that over land, precipitation mainly comes from frequent thunderstorms.
This leads naturally to S6, which notes that most precipitation falls as heavy intermittent convective showers with thunder and lightning.
Thus the correct sequence is R, S, P, Q.
Answer:Option B: RSPQ.