I am very confused about the two sentences I am going to make up.
(1) The black, the white and the red marble(s) on the desk are mine.
Please note that in my next example, assume that there are several marbles in each color.
(2) A black, a white and a red marble is or are to be removed from the box.
In (1), do I need to pluralize the word "marble"?
In (2), which verb works better "is" or "are"?