Find the hypothesis in the research background and underline
it. a hypothesis is a proposed explanation for an observation, which can then be tested
with experimentation or other types of studies.

the answer is tropical areas. the tropical areas obtain more

radiant energy from the sun than they lose to space through terrestrial

radiation, and vice versa for polar areas. earth has an energy remaining in the

tropics and an energy scarcity for the polar areas.

explanation:

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

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