Instructions: The passage below consists of six sentences. The first and the sixth sentences are given (S1, S6). The middle four sentences have been removed and jumbled up, labelled P, Q, R and S. Find the proper order for the four sentences.
S1: Metals are today being replaced by polymers in many applications.
P: Above all, they are cheaper and easier to process, making them a viable alternative to metals.
Q: Polymers are essentially long chains of hydrocarbon molecules.
R: Today, polymers as strong as metals have been developed.
S: These have replaced the traditional chromium-plated metallic bumpers in cars.
S6: Many Indian Institutes of Science and Technology run special programmes on polymer science.