Final answer:
The corrected text resolves three subject-verb disagreements by ensuring that the verbs 'was,' 'has,' and 'suggest' correctly match their subjects for accurate grammar.
Step-by-step explanation:
Proofreading the provided text, I have identified and corrected three subject-verb disagreements. Here are the corrections made:
- The fate of the diamond, along with several other high profile gems, was unknown after the Franco-Spanish war of 1635...
- Neither time nor conflict has dimmed its brilliance.
- The twin eighty-year-old brothers suggest that the value of the now cut and polished 90 carat diamond has already increased by at least 50%.
It is important that the verbs 'was,' 'has,' and 'suggest' agree with their respective subjects to maintain grammatical consistency throughout the text.