Changing Scientific Knowledge

Question 1

A class is studying two different explanations for why the long-necked dinosaur Brachiosaurus could reach high trees. Explanation A was proposed after one bone was found with a short neck. Explanation B was proposed after scientists examined three different skeletons, a fossilized trackway, and a recent 3‑D scan of the vertebrae. Which statement best follows how scientists decide which explanation is strongest?

Accepted Answer

The explanation that is backed by the most evidence from several sources is the best one.

Answer

The explanation that was written down first is the best one.

Answer

The explanation that looks the most surprising is the best one.

Answer

The explanation that comes from the most famous scientist is the best one.

Question 2

Which sentence below tells about a dinosaur theory that scientists revised because of fresh fossil evidence?

Accepted Answer

Scientists once believed all dinosaurs were cold‑blooded, but new fossil bone chemistry showed many grew quickly like warm‑blooded animals, so the idea was changed.

Answer

Scientists think the huge dinosaur Argentinosaurus was the biggest land animal because its massive leg bones were found.

Answer

Scientists originally thought Stegosaurus plates were only for protection, and recent fossils have confirmed that.

Answer

Scientists say that all dinosaurs lived in very cold climates because ice fossils were discovered near their remains.

Question 3

Which statement best illustrates a dinosaur hypothesis that was revised after a new fossil discovery?

Accepted Answer

Paleontologists originally thought the huge sauropod Apatosaurus ate only low‑lying plants because its neck was believed to be too weak to reach high foliage; later, a fossil with specially shaped neck vertebrae demonstrated the neck could support a raised head, leading scientists to revise the feeding‑height idea.

Answer

Scientists originally said the feathered dinosaur Archaeopteryx could not fly because its wings were too small, but a new fossil showing larger wing bones proved it could soar across oceans.

Answer

Scientists once thought all Tyrannosaurus rex had short arms, but a newly found T. rex skeleton with unusually long forearms showed that some individuals had longer arms, so the idea about arm length was changed.

Answer

Researchers believed Stegosaurus walked on its hind legs because its tail was stiff, and finding a fossil with a flexible tail proved it could not walk upright.

Try three questions

Which sentence below tells about a dinosaur theory that scientists revised because of fresh fossil evidence?

Which statement best illustrates a dinosaur hypothesis that was revised after a new fossil discovery?

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