Present Day Heat Flow from Within Earth Is Twice as High

question 69

Multiple Choice

Present day heat flow from within Earth is twice as high as could be expected from radioactivity's contribution. This suggests that

• A) more radioactivity is occurring than what scientists have accounted.
• B) volcanic action contributes more than scientists presently understand.
• C) Earth used to be much hotter.
• D) movement within the core causes heating by friction.