Question

2. Alvarez saw that fossils found below the clay layer in the_______?

Answer 1

Alvarez saw that fossils found below the clay layer in the **Geological record**. This clay layer, known as the Cretaceous-Paleogene (K-Pg) boundary, is significant because it marks the extinction event that wiped out the dinosaurs around 66 million years ago. The fossils below this layer generally belong to species that existed before this mass extinction, while those above it are from species that survived or evolved afterward. If you need more context or further information, feel free to ask!