For proper ventilation of building, windows must be open near the bottom and top of the walls so as to let pass
A
In more air
B
In cool air near the bottom and hot air out near the roof
C
In hot air near the roof and cool air out near the bottom
D
Out hot air near the roof
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B
In cool air near the bottom and hot air out near the roof
b (b)Density of hot air is lesser than the density of cold air so hot air rises up.
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