1. Cause 1
   1. Cause 1
      1. Cause 1
      2. Cause 2
   2. Cause 2
2. Cause 2
   1. Cause 1
      1. Cause 1
   2. Subtopic 2
3. Cause 3
   1. Cause 1
   2. Cause 2
4. Cause 4
   1. Cause 4
   2. xmind.net/blog/en/ brainstorming-template
5. Cause 5
   1. Cause 1
6. Cause 6