In each question, the first and the last sentences of the passage are numbered S1 and S6 respectively. The rest of the passage is split into four parts. These four sentences are jumbled. Read the sentences and identify their correct and logical order.

---

S1: A force of exists between everybody in the universe.
P : Normally it is very small but when the one of the bodies is a planet, like earth, the force is considerable.
Q : It has been investigated by many scientists including Galileo and Newton.
R : Everything on or near the surface of the earth is attracted by the mass of earth.
S : This gravitational force depends on the mass of the bodies involved.
S6: The greater the mass, the greater is the earth's force of attraction on it. We can call this force of attraction gravity.
The Proper sequence should be: