Question

2) The atmosphere extends to an altitude of
a) 200 km b) 500 km c) 320 km d) 600 km
3) The gas used in filling weather balloon is
a) oxygen b) helium c) nitrogen d) water vapour
4) Which gas is released during respiration?
a) NO 6) CO c) CO₂ d) SO₂ ​

Answer 1

Answer:

2-d

3-b

4-c

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