Twin powers in charge here, properly including work with oxygen (7)
I believe the answer is:
duopoly
'twin powers' is the definition.
The definition suggests a singular noun which matches the answer.
'charge here properly including work with oxygen' is the wordplay.
'charge here properly' becomes 'duly' (I am not sure about this - if you are sure you should believe this answer much more).
'including' is an insertion indicator.
'work' becomes 'op' (abbreviation for opus).
'with' says to put letters next to each other.
'oxygen' becomes 'o' (atomic symbol for oxygen).
'op'+'o'='opo'
'duly' going around 'opo' is 'DUOPOLY'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for duopoly that I've seen before include "Form of market domination" , "Where two companies dominate a market" , "Limited competition" .)