Look out of your window and you will most probably find the answer (or at least a good hint).
The riddle had been edited! The answer is still the same.
I relate a river with a bridge, an edge is a bridge if and only if it is not contained in any cycle. It consists of specific symbols, e.g. G=(V,E) and is part of the theory. It is made up of points or nodes and model relations between objects. So I guess it is a
The symbol, a part.
square, circle, triangle are symbols, part of the logo
The node, an object.
i suppose we can treat them as nodes?
Look out of your window and you will most probably find the answer (or at least a good hint).window refers to Windows (computer), at the edge there's the logo!
What about a
Seems self explanatory to me - a symbol or picture of a cloud is always a part of the sky
The node, an object
As in cloud computing!
The first one:
Water - water in a river, the water cycle
But I'm not sure about the others yet...