Question

You are a biologist working in Montana when you find a fossilwedged between two ancient layers of sedimentary layers. Whattechnique would be the best tool to use to find the age of thefossil?
Answer
1. Use the radioisotopes sandwiched into the two layers around thefossil to approximate the range of time that the organism wasalive.
2. Use carbon dating of the fossil's carbon 12 isotopes.
3. Use radioactive dating of the fossil's uranium-238isotopes.
4. Use the ratio of carbon-12 to carbon-14 isotopes in the fossilto 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 mostalarming evidence warning of an ongoing sixth mass extinctionevent?
Answer
1. The thoroughly documented extinction of species in therainforest.
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 nowinterbreeding.
5. That previous extinctions rates increased with increased globaltemperature.