Fossil fuels have been used for years as a source

of energy. Even though there are many negative

issues associated with the use of fossil fuels, they

continue to be used to a great extent. This is

most likely because

(1) they have been commercially available as an

energy source

(2) there are alternatives to these types of fuels

(3) they have had a positive effect on global

temperatures

(4) fossil fuels can be burned to produce large

quantities of carbon dioxide

The best answer is (1)

Fossil fuels are commercially available as an energy source.

They are very easy to find. More and more extractions of fossil fuels is going on everyday. With advancement in science and technology, the refineries and extraction procedures have improved a lot. This makes their availability even better.

Fossil fuels are also easily combustible. Most combustion engines need to be powered with little amount of fuel to produce large amount of energy. Very large amounts of electricity can be generated from fossil fuels.