Question

2./ Fill in the blanks:
i. The layer of atmosphere in which ionisation begins to occur is called
ii. Greenhouses are used to
iii. Long-distance radio communication is possible in
iv. The air in atmosphere is a
of many gases.
and
The percentage of
present in air varies.
V.​

Answer 1

1. Answer: more commonly known as the ionosphere. This region is an approximately 300-km- (190-mile-) thick layer starting about 100 km (60 miles) above Earth's surface in which the atmosphere is partially ionized by ultraviolet light from the Sun, giving rise to enough electrons and ions to affect radio waves.