Since 1960, the gap between rich and poor, as measured by GNP per capita, has

Question

a.
decreased, then increased since 1980.
b.
increased, then substantially decreased since 1980.
c.
increased, then substantially increased since 1980.
d.
decreased, then substantially decreased since 1980.
e.
has remained constant since 1980.




Solar energy is a(n) __________ resource.
a.
renewable
b.
potentially renewable
c.
nonrenewable
d.
exhaustible
e.
perpetual