Means by which natural ventilation takes place

Natural ventilation takes place when the natural movement of air transfuses air. Natural movement of air keeps the buildings or the surrounding afresh. Typically windows, holes in the roof, and doors.

Explanation:

Natural movement of air without the help of mechanical tools to and from a place of higher concentration to a lower concentration or vice versa. Natural ventilation usually takes through windows and doors. When windows open they create a window driven ventilation.

By opening and closing windows we can manage the air flow.

it's actually d for edge-nuity.