1
Yes. It is a proper noun.
It is capitalized only when used as a proper noun grammatically.
Yes. It is a noun, therefore should be capitalized.
First part , Generic name .
Oranges
oranges are the BEST!!!!!
A "score" of anything is twenty of that thing. So a score of oranges equals twenty oranges.
Fifteen apples and seven oranges.
As a title of a school course, yes. As a word in a sentence such as, "The drug affected his brain chemistry," no.
There is no standard collective noun for oranges, in which case a noun that suits the situation is used, for example, a bagof oranges, a box of oranges, a crate of oranges, etc.
2 dozen of oranges = 24 oranges.