Question

naming the boundary
observe the line visible across the hell creek area. this line is the boundary between two formations. the top is called the tullock formation and the bottom the hell creek formation.
what is the new term for the boundary between the two formations?
k-t boundary
k-pg boundary
asteroid boundary
extinction line
impact margin

Explanation:

The boundary between the Cretaceous and Paleogene periods is now known as the K - Pg Boundary. It replaced the older term K - T Boundary. The K - Pg boundary is associated with the mass extinction event that led to the demise of the non - avian dinosaurs.

Answer:

B. K-Pg Boundary