Fill in the blanks.
(a) The slow protess of conversion of dead vegetation into coal is called
(b) Coal and petroleum are formed from the dead remains of organisms and are known as
(c) The black thick liquid with smell is known as coal tar.
(d) During the processing of coal to get coke, coal tar and …… are also obtained.
(e) The process of separating the various constituents of petroleum is known as
(f) Excessive burning of fossil fuels is a major cause of
(b) fossil fuels
(d) coal gas
(f) air pollution