2. Fill in the blanks.
(a) Burning of wood and coal causes_________ of air.
(b) A liquid fuel, used in homes is_________ .
(c) Fuel must be heated to its___________ ___________ before it starts burning.
(d) Fire produced by oil cannot be controlled by__________ .
(a) Burning of wood and coal causes pollution of air.
(b) A liquid fuel, used in homes is LPG(Liquified Petroleum Gas) .
(c) Fuel must be heated to its ignition temperature before it starts burning.
(d) Fire produced by oil cannot be controlled by water .