Concept:The question tests the logical sequencing of sentences describing the process of melting of solids when heated.
Explanation:S1 states that increasing temperature raises kinetic energy of particles in solids.
Sentence Q follows logically: due to increased kinetic energy, particles vibrate faster.
Next, sentence S: the heat energy supplied overcomes inter-particle forces of attraction.
Then sentence R: as a result, particles leave their fixed positions and begin moving freely.
Finally, sentence P: the stage is reached when the solid melts into a liquid.
S6 defines the temperature at which this happens as the melting point.
Thus, the correct order is S1, Q, S, R, P, S6.
Answer:Option A: Q, S, R, P