This prints "This is the question", and then when you click on it it prints "This is the answer":
EventHandler["This is the question",
{"MouseClicked" :> Print["This is the answer"]}]
This opens a new notebook in which it prints "This is the question" followed by "This is the answer".
NotebookPut[
Notebook[{Cell["This is the question", "Text"],
Cell["This is the answer.", "Text"]}]];
But how can I open a new notebook and print "This is the question" and then only print "This is the answer" when someone clicks on "This is the question", i.e. get the same effect as with the first code but in a newly opened notebook?