Excerpt 3. Extinction of the Dinosaurs

What era did the extinction of the dinosaurs mark the end of?

• Mesozoic Era

• Paleozoic Era

• Cenozoic Era

• Triassic Period

What was the climate like during the Late Cretaceous period?

• Milder than today’s

• Hotter than today’s

• Colder than today’s

• Similar to today’s

What is one reason paleontologists believe the dinosaurs went extinct?

• Climatic alterations due to plate tectonics

• A large asteroid impact

• Volcanic eruptions

• Disease

Why is the hypothesis of a simple climatic change related to sea levels considered insufficient?

• Dinosaurs survived previous sea level changes

• Cold-blooded animals survived

• The climate changes were not extreme

• There is no evidence of sea level changes

What element is found in high concentrations in the boundary clay between the Cretaceous and Cenozoic rocks?

• Iridium

• Gold

• Silver

• Iron

What is the proposed size of the asteroid that may have caused the extinction of the dinosaurs?

• 10 to 15 kilometers across

• 5 to 10 kilometers across

• 15 to 20 kilometers across

• 20 to 25 kilometers across

What effect did the asteroid impact have on the Earth's climate?

• Cut off sunlight and decreased temperatures

• Increased sunlight and temperatures

• Caused continuous rainfall

• Stabilized the climate