i believe that it is chromosomes
The extermination of the dinosaurs, the start of a rise to dominance of mammals and a meteorite effect in mexico marks the boundary among the mesozoic and the cenozoic or as named as the k-p boundary. In addition, the cretaceous paleogene (K–Pg) boundary which is previously recognized as the cretaceous tertiary (K–T) boundary is a geological signature typically a thin band of rock.
Answer:
A
Explanation:
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