A scientist is studying a section of exposed sedimentary rock layers, that are near a fault line. Using geologic principles name the principle that you think could explain this observation and give a reasonable explanation as to why you think so. Here is observation:
Layer A- top layer-contains fossils dated at 20,000 years old.
Layer B - next layer down- contains fossils dated at 100,000 years old.
Layer C-third layer down- contains fossils dated at 400,000 years old.
Layer D- bottom layer- contained fossils 800,000 years old.

PLEASE HELP

Question

A scientist is studying a section of exposed sedimentary rock layers, that are near a fault line. Using geologic principles name the principle that you think could explain this observation and give a reasonable explanation as to why you think so. Here is observation:
Layer A- top layer-contains fossils dated at 20,000 years old.
Layer B - next layer down- contains fossils dated at 100,000 years old.
Layer C-third layer down- contains fossils dated at 400,000 years old.
Layer D- bottom layer- contained fossils 800,000 years old.

PLEASE HELP