Use coordination to combine each pair of sentences below into one sentence. Use a word or phrase that expresses the relationship shown in parentheses.

1.Most people collect stamps only as a hobby. Some people collect stamps as an investment. (contrast)
2.A stamp's rarity affects its value. The way the perforations are made affects the stamp's worth. (addition)
3.A stamp was missing a single perforation. Its value was greatly reduced. (result)
4.A stamp printed in British Guiana in 1856 is the world's rarest stamp. It is the most valuable stamp of all. (result)

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1. Most people collect stamps only as a hobby, but some people collect stamps as an investment.

1. Most people collect stamps only as a hobby, while some people collect stamps as an investment. (contrast)

2. A stamp's rarity affects its value, and the way the perforations are made also affects the stamp's worth. (addition)
3. The missing of a single perforation greatly reduced the value of a stamp. (result)
4. A stamp printed in British Guiana in 1856 is the world's rarest stamp, therefore making it the most valuable stamp of all. (result)