Room are provided with the ventilators near the roof. Why?

Arrange the following steps in a sequential order to explain the formation of conventional currents through ventilation. (a) the cold air enters into the room through windows from high pressure to low pressure region (b) hot air in the room is less denser and it raises up (c ) the rooms are provided with ventilators at the top (d) hot air passes out through the ventilators it creates low pressure region in the room

Why are doors provided with handles near the outer edges, far away from the hinges ?

Define the rate of ventilation.

Statement-1: Ventilators are provided at the top of the room. Statement-2: Their purpose is to bring oxygen for breathing.

The alveolar ventilation is the

You are provided with three watch glasses containing milk, petrol and mustard oil, respectively. Suppose you bring a burning candle near these materials one by one, which material(s) will catch fire instantly and why?