Across
- 2. a diagram that shows rock formations in a region
- 4. the age of a natural material in years
- 7. the remains or impression of a prehistoric organism in its petrified state
- 9. a word or expression with a specific meaning especially when used in relation to a subject
- 10. a fossil used for dating and correlating the strata in which it is found
- 12. a period in time typically marked by a event
- 13. when species vanish much faster than they are replaced
Down
- 1. the use of energy released by inorganic chemical reactions in order to produce food
- 3. the chemical process in plants when they are exposed to sunlight
- 5. the process where living organisms develop from its earlier forms
- 6. an artificial lake where water is stored
- 8. the time it takes for a quantity to reduce half its initial value
- 11. a long and distinct period in history marked by a feature