5168. S1: Plastic containers are being used more and more to package soft drinks, milk, oil, fruit juices, ketchup, etc. P: Most people think that this is the right thing to do, as it is economical. Q: Plastic containers are cheap and light. R: It is easier to transport materials packaged in them than in glass bottles. S: They also involve the least transport costs. S6: Yet as plastics do not decompose by bacteria or naturally in the air, they are a big threat to the environment. The Proper sequence should be: