common
No.
Examples of proper nouns for the common noun 'war' are "War and Peace" by Leo Tolstoy, the 1989 movie "War of the Roses", World War II, or the Revolutionary War.
No, unless it is the name of a person.
proper
A poor substitute for a proper apology from a man who doesn't mean what he says. The second most common use is as a lethal weapon against said man.
eewr
As a name of a road , Park Avenue', it is a proper noun, and both words star with a capital letter. However, when used separately, as 'the park, or 'the avenue', they are common nouns and so not need a capital letter.
common
common and proper
daisies roses
It is a proper noun, because it is the name of a specific thing.
common