The natural order of things in Iceland? (4,5)
I believe the answer is:
food chain
'things in iceland?' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'the natural order' is the wordplay.
'the natural' becomes 'food' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'order' becomes 'chain' (chain is a kind of order).
'food'+'chain'='FOOD CHAIN'
'of' is the link.
Can you help me to learn more?
(Other definitions for food chain that I've seen before include "hierarchy" , "Natural order of consumption" , "string of sausages?" .)