If you want to use keys with an external document, you have to first change the _____ node so that it points to a location path within that document.

A(n) __________ structure is commonly known as a loop.

Fill in the blank(s) with the appropriate word(s).

With most OOP languages, you must ____ components, or sign them up so that they can react to events initiated by other components.

A. register B. activate C. instantiate D. create