1. According to the article, why don’t scientists know exactly what T-rex mouths looked like? Use text evidence. The article states that scientists do not know exactly what T-rex mouths looked like because “dinos became extinct, or died out, about 65 million years ago.”
(RI.3.1 Text Evidence)
2. What can you learn from the two T-rex drawings at the top of the page? From these two drawings, you can learn two ideas about what T-rex looked like. The drawing on the left shows what most scientists used to think the dinosaur looked like. The one on the right shows what many scientists think now. It shows T-rex with lips over its teeth.
(RI.3.7 Using Visuals)
3. Why do some scientists think T-rex had lips covering its teeth? Some scientists think this because they compared fossils of T-rex teeth with crocodile teeth. Crocodiles do not have lips. As a result, their teeth often break during eating and fighting. T-rex teeth did not have the same damage, so these dinos may have had lips protecting their teeth.
(RI.3.3 Cause and Effect)