You are presented with the question "What with the vanes rotating causes air here to move?" and the following answer choices: 
- It reaches the dew point
 - heat to cooler objects
 - whale movement
 - it flows to a lower level
 - Earth's axis of rotation is tilted
 - vanes on submarins
 - Martian winds rotating.
 - 180 revolutions per minute.

Now knowing that the vanes rotating in an electric fan causes air to move and an electric fan makes 180 revolutions per minute, choose the best answer.


 

        180 revolutions per minute. 