Are they unique in bone structure? (4)
I believe the answer is:
ones
'are they unique' is the definition.
The definition suggests an adverb but the answer is not.
'in bone structure?' is the wordplay.
'in' indicates a hidden word.
'ONES' is hidden in the letters of 'bone structure'.
Can you help me to learn more?
(Other definitions for ones that I've seen before include "Units" , "1 & 1 & 1" , "Individuals" , "Singles" , "Aces" .)