Crossword Genius

Choice of mainstream parties to defend a scientific research site (10)

Ross

I believe the answer is:

laboratory

I'm a little stuck... Click here to teach me more about this clue!

'scientific research site' is the definition.
I know that both 'scientific' and 'research' relate to this answer. I also know that both the answer and definition are singular nouns

'choice of mainstream parties to defend a' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is found within the answer.
'to' is within the answer.
'a' is within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

(Other definitions for laboratory that I've seen before include "Place of scientific research" , "Experimental facility" , "workplace" , "Where researchers work" , "Place for experimentation" .)

I've seen this clue in The Guardian.
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