I did not find a question type that would allow me for a tree-style answering options. I want users of a survey to select topics from a hierarchical list. They should be able to select several topics or sub-topics by clicking on a hierarchical structure.
Is this possible at all?

+ O Plants
- O Animals
   L O Mammals
       L O Primates
       ....
+ L O Birds
 

This type of question does not exist out of the box. You would have to do some work around.

Yes, it is possible.
 
But you should have answered the questions at the beginning about your version and the hosting.
And please provide a lss export of this question.

Joffm