Big Book Test 03 Section 3 Q6

GRE Verbal Problem Solving
1

To test the ------- of borrowing from one field of
study to enrich another, simply investigate the extent’
to which terms from the one may, without forcing,
be ------- the other.

There is no contrasting word in the above sentence, at the same time both ideas have blank, so the blank must me syno. Is it right approach?

2

Yes, the ideas are supporting each other

Where would you look in the sentence for information about what should go in the blank?