Over the past 100 million years of Earth history, it is known that the magnetic poles have reversed themseves ______ times.

a - 0
b - 2
c - many
d - 25


c - many

Environmental & Atmospheric Sciences

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Given the following diagram, describe what happens electronically between these two molecules.

A. Hydrogens on oxygen W becomes slightly positively charged due to the oxygen molecule. B. Oxygen A becomes slightly positively charged due to the protons on the water molecule. C. Oxygen B becomes slightly positively charged due to the protons on the water molecule. D. Oxygen A becomes slightly negatively charged due to the oxygen molecule. E. none of the above

Environmental & Atmospheric Sciences

During alpha emission, the mass number is reduced by ________ and the atomic number is decreased by ________

A) 2; 4 B) 4; 2 C) 3; 6 D) 6; 4

Environmental & Atmospheric Sciences

Which of the following combinations represents two cloud types that can produce precipitation?

A. cumulonimbus and stratocumulus B. nimbostratus and altostratus C. cumulonimbus and nimbostratus D. nimbostratus and cirrus

Environmental & Atmospheric Sciences

Most of the countries experiencing food-security problems are in what region? (23 of the 28 countries are found here.)

A) Asia B) Middle East C) north Africa D) southeastern Europe E) sub-Saharan Africa

Environmental & Atmospheric Sciences