My question was deleted because it was "incomplete", but I'll answer again.
Simple
This sentence is simple because it contains one singular idea. It may be incorrectly identified as compound because the subject is compound (Forest rangers and volunteers). This is an easy mistake.
Hope this helps!! Good luck, mate. :)
You can say that you watched tv, did sport, learn for school, clean you room,...
You can imagine something. Think of what you can posibly doing at home.
None of the above (N.D.A in Portuguese)
My hobby is what? Surfing
Any part of the sentence that answers 'what' is the Direct Object