Directions: The first and the last parts of a sentence are numbered 1 and 6. The rest is split into four parts and labelled P, Q, R and S. These four parts are not given in their proper order. Read the sentence and find out which of the four combinations is correct.

1. Science is P. that builds and organises Q. knowledge in the form R. of testable explanations and predictions S. a systematic enterprise
2. about the world