Multiple choice

For proper ventilation of a building, windows must be open near the bottom & the top of the walls so as to let pass

  1. in more air

  2. in cool air near the bottom & hot air out near the roof

  3. in hot air near the roof & cool air out near the bottom

  4. out hot air near the roof

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Effective ventilation relies on convection currents. Cool, dense air enters through lower windows, while warm air (which is less dense and rises) exits through openings near the ceiling.

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