Critical evidence for the Cretaceous-Tertiary boundary impact included _________________.
A)dinosaur fossils worldwide just above the layer of impact debris
B)an iridium anomaly in a thin layer of rock 65 million years old
C)recovery of very large pieces of meteorite
D)discovery of a crater covered by jungle vegetation in Brazil
E)an Iranian deposit of reddish iron bearing strata

Question

Quizplus · Accepted Answer

The iridium anomaly in a thin layer of rock 65 million years old provided critical evidence for the Cretaceous-Tertiary boundary impact, as iridium is rare in the Earth's crust but abundant in meteorites.

Answer: A 
 Dinosaur fossils worldwide just above the layer of impact debris also provided important evidence for the Cretaceous-Tertiary boundary impact. The extinction of the dinosaurs and many other species at this time is thought to be linked to the impact.

Answer: D 
 The discovery of a crater covered by jungle vegetation in Brazil provided further evidence for the Cretaceous-Tertiary boundary impact. This crater, known as the Chicxulub crater, is believed to be the site of the impact that caused the mass extinction.

Therefore, the best choices are B and A.

Critical Evidence for the Cretaceous-Tertiary Boundary Impact Included _________________