While the researcher's initial findings were hailed as a significant breakthrough, subsequent studies have introduced a degree of ______ into the prevailing consensus, suggesting that the phenomenon is far more ______ than previously assumed.

The correct answer to the question "While the researcher's initial findings were hailed as a significant breakthrough, subsequent studies have introduced a degree of ______ into the prevailing consensus, suggesting that the phenomenon is far more ______ than previously assumed." is Option C: skepticism ... convoluted.

The other options — A) ambiguity ... straightforward, B) certainty ... intricate, D) clarity ... facile — are incorrect for this GRE Exam Prep question. As explained above: If a breakthrough is questioned, 'skepticism' is introduced. This implies the phenomenon is 'convoluted' (complex) rather than simple, aligning with 'far more ______ than previously assumed'.