You are presented with the question "What is used to determine the age of fossils?" and the following answer choices: 
- Calcium carbonate
 - dinosaurs
 - a barometer
 - electron microscope
 - a thermometer
 - a decay curve
 - chemical equations
 - Physical weathering

Now knowing that radioactive dating is used to determine the age of fossils and radioactive dating requires the use of a decay curve, choose the best answer.


 

      a decay curve   