In this section, each item consists of six sentences of a passage. The first and sixth sentences are given as SI and S6. The middle four sentences in each have been jumbled up and labeled as P, Q, R, and S. You are required to find the proper sequence of the four sentences and mark your response accordingly.

S1: In ancient times, wood was the most common source of heat energy.
P:  The energy of flowing water and wind was also used for limited activities. 
Q: The exploitation of coal as a source of energy made the industrial revolution possible. 
R: Increasing industrialisation has led to a better quality of life all over the world. 
S: It has also caused the global demand for energy to grow at a tremendous rate.
S6: The growing demand for energy was largely met by fossil fuels – coal and petroleum.