SORU: aşağıdaki parçada numaralanmış yerlereuygun düşen sözcük ya da ifadeyi bulunuz
People are in a constant search for different sources of
energy. Today, we meet most of our energy needs by
burning fossil fuels (16)---- coal, oil and natural gas.
(17)----, one problem with fossil fuels is that when burned
for energy, they release carbon dioxide and other gases.
For instance, burning these fossil fuels releases large
amounts of greenhouse gases, which are also released
when they are retrieved from the earth. Namely,
extracting the fuels and processing them (18)---- their
final forms require fossil fuels, and thus produce carbon
dioxide. Another problem is that fossil fuels give a
one-time-only burst of energy. Therefore, since the
supply of fossil fuels is limited and will finish one day,
civilisation will have to wait millions of years before any
more (19)----. That is why people will have to (20)---- a
diversity of fuel sources to produce energy in the future.