The caffeine content of coffee varies greatly, depending on the beans, how they're roasted, and other factors, but the average for an 8-ounce cup is about 100 milligrams (mg).
No, 'cat' is a common noun, a word for any cat of any kind. A proper noun is the name of a person, a place, a thing, or a title; for example: Cat Deeley, host of TV series 'So You Think You Can Dance'.
A proper noun is the name of a specific person, place, or thing; for example: 1  United States Secret Service, Department of Homeland Security. 2  South African Secret Service, National Intelligence Co-ordinating Committee. 3  Australian Secret Intelligence Service, Department of Foreign Affairs and Trade.