1. "oxygen minimum zone" refers to: (definition)
2. the earth’s known reserves of fossil fuels (oil, natural gas, coal) are approximately equivalent to the total amount of solar energy that reaches earth over: (approximate period of time)
3. what is the average rate at which temperature increases going downward into the earth’s crust?
4. the term "geothermal gradient" refers to: temperature increases are you get closer to earth's core
5. crude oil originally starts out as:
6. in what area(s) of the ocean does most organic matter burial typically take place? areas bordering continents