Passage Summary: Because we found bird fossils that are older than the fossils of the dinosaurs we thought they came from, the author claims birds couldn't have come from dinosaurs at all.

Conclusion: The theory that birds are descendants of dinosaurs is incorrect.

Reasoning: Newly discovered bird fossils are 20 million years older than the fossils of the dinosaurs previously thought to be their ancestors.

Analysis: The author is making a massive leap from a single chronological discrepancy to a total rejection of a biological theory. Just because these specific dinosaur fossils are younger than these specific bird fossils doesn't mean birds didn't descend from *any* dinosaur; it might just mean we haven't found the right, older dinosaur fossils yet. The argument fails to account for the incompleteness of the fossil record. Look for an answer that identifies this failure to consider that the 'ancestor' might have existed much earlier than the specific fossils we've found so far.