You are a biologist working in Montana when you find a fossil wedged between two ancient layers of sedimentary layers. What technique would be the best tool to use to find the age of the fossil?
Answer
1. Use the radioisotopes sandwiched into the two layers around the fossil to approximate the range of time that the organism was alive.
2. Use carbon dating of the fossil's carbon 12 isotopes.
3. Use radioactive dating of the fossil's uranium-238 isotopes.
4. Use the ratio of carbon-12 to carbon-14 isotopes in the fossil to approximate the time the fossil was formed.
5. Use carbon dating of the fossil's carbon 14 isotopes.

Which of the following facts or phenomena likely represent the most alarming evidence warning of an ongoing sixth mass extinction event?
Answer
1. The thoroughly documented extinction of species in the rainforest.
2. That we are currently in an ice-age.
3. The likelihood of an asteroid striking the earth.
4. The fact that polar bears and grizzly bears are now interbreeding.
5. That previous extinctions rates increased with increased global temperature.