What is a hardened sediment that contains the impression of a bone

List the advantages and disadavantages of the switch from persistent chlorinated hydrocarbon pesticides (such as ddt) to nonpersistent organophosphate pesicides. have the benefits of the switch outweighed the disadvantages? explain.

This group of organisms perform the process of ammonifcation. a. herbivores b. decomposers c. carnivores c. plants

9. the history of life on earth is recorded in