The following sentences form a paragraph. The first and the last sentences of the paragraph are given. The rest of the sentences are numbered as P, Q, R and S. These four parts are not given in their proper order. Read the sentences and choose the alternative that arranges them in correct order.

1.Forest fires are terrifying    

P. and even burn the roots underground.

Q. Even a tiny mishap could trigger a huge fire.

R. Then, such fires kill trees and other plants,

S. and most of the time are very destructive.

6.A blackened wasteland is what remains in the end.