Passage Summary: Carrillo uses math and genetics to estimate when primates first appeared, but Olson thinks that's just guessing because the physical fossils don't go back nearly that far.

Conclusion: Carrillo concludes that the first primates likely emerged approximately 81.5 million years ago.

Reasoning: Carrillo bases this on a statistical model of genetic diversity, while Olson argues this is mere speculation because the oldest fossils found are only 55 million years old.

Analysis: The disagreement centers on the validity of Carrillo's estimate. Carrillo presents the 81.5 million-year figure as a conclusion 'strongly supported' by a model, whereas Olson explicitly labels it 'sheer speculation.' When using the Agree/Disagree test, focus on the status of that specific date estimate. Carrillo would agree it is a well-founded scientific conclusion; Olson would disagree, maintaining it lacks the necessary fossil evidence to be anything more than a guess.