Passage Summary: Scientists found T-rex tissue that looks like chicken tissue, and they're using this as proof that dinosaurs and birds are family.

Conclusion: The discovery of T-rex collagen similar to chicken collagen supports the theory that dinosaurs and birds are closely related.

Reasoning: Analysis showed that preserved soft tissue from a T-rex contained collagen proteins similar to those found in modern chickens.

Analysis: To evaluate this argument, we need to determine if the 'similarity' mentioned is actually significant. If T-rex collagen is similar to chicken collagen, but also similar to the collagen of every other living creature, then the 'evidence' doesn't specifically link dinosaurs to birds. We should look for an answer choice that asks about the uniqueness of this similarity. If the protein is common across many animal groups, the argument's strength evaporates; if it's unique to birds and dinosaurs, the argument is much stronger.