Sediments and rocks that are moved around by agents of erosion, tell us the history of where they started. If the White Cliffs of Dover in England, were once sea shells, what does that tell us about what happened in the past in that area?

then that particular organisms become extinct.

economic impact of malaria is estimated to cost africa $12 billion every year. this figure factors in costs of health care, absenteeism, days lost in education, decreased productivity due to brain damage from cerebral malaria, and loss of investment and tourism.

not sure if this what   you'r looking for would be percent composition

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation: