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.

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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 a 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.
The Proper sequence should be: