How much carbon dioxide was present in Earth's atmosphere 4 billion years ago?
A. about the same amount as now
B. much less than now
C. much more than now
Answer: C
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What is the leading threat to commercial shellfisheries?
a. oil spills b. PCBs c. hypoxia d. mercury e. plastics
A relatively narrow downburst, less than four kilometers wide, is called a ____
A) microburst B) macroburst C) funnel cloud D) mesocyclone
The main reason hurricanes don't develop over the South Atlantic Ocean adjacent to South America is because the
a. Coriolis force is too small there. b. pressure gradient force is too weak in that area. c. surface water temperatures are too cold. d. air at the surface is always diverging. e. winds don’t spin into the right direction.
The Antarctic ice sheet is an example of a/an
A. mountain glacier. B. continental glacier. C. alpine glacier. D. valley glacier.