What does a scientist need to know to figure out the relative age of a rock layer? A. the age of the layers above and below the rock

B. the age of the fossils of the top layer

C. the rate of decay for all elements in the rock

D. the radioactive element in the rock

The rate of decay C

To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

A is the answer, this is because deposition has been happening on earth for ages so as time goes by more deposits form layers on earth, including the remains of animals and plants that would later become fossils.

there is no

explanation:

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.