. Fill in the blanks in the following sentences
(a) Coal is one of the ________ used to cook food.
(b) When heated in air, coal burns and produces mainly ________ gas.
(c) Coal tar is a black, thick ________ with an ________ smell.
(d) Petroleum, ________ and ________ are fossil fuels.
(e) Forests and coal are ________ natural resources.
Ans. (a) fuels
(b) carbon dioxide
(c) liquid, unpleasant
(d) coal, natural gas