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.
Answer: C
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The removal of a single or small groups of mature trees is called
A. selective cutting. B. seed-tree cutting. C. clear-cutting. D. shelterwood cutting. E. strip cutting.
This diagram shows magnetic stripes on either side of the midocean ridge. How many different ages of stripes are represented in this diagram?
A) Two
B) Three
C) Four
D) Six
E) Eleven
POPs such as dioxins and PCB's are transported into arctic ecosystems and food chains by
A) global air patterns and then deposited on snow from where they enter streams and plankton. B) being eaten by fish when toxic materials are dumped into oceans. C) local industries run by native people who use toxic chemical processes. D) ocean currents, which contaminate local streams.
For the following acid-base reaction, identify which salt is formed. HCl + NaOH ? ???? + H2O
A. H3OCl B. NaOH2Cl C. NaOH2 D. NaCl E. none of the above