4. monarch migration

5. Isotopes What good are they?

7. Some are radioactive and some are stable

9. date fossils

10. In nature, an element occurs as a mixture of isotopes which can vary according to geography and other environmental factors

11. How can isotopes be used to study animal migration?

12. Anthropological and forensic problems?

14. As well as in determining past climates from oxygen isotopes in ice and ocean organisms

15. Which oxygen isotope gets trapped in ice (as a result of precipitation) and in the shells of ocean organisms is temperature dependent and the ratio can be used to determine past temperatures.