You are presented with the question "when is it often uncomfortable?" and the following answer choices: 
- at room temperature
 - Plant growth is reduced
 - cloudy and rainy weather
 - pillows
 - heat or cold
 - sleeping
 - Riding a bike
 - when cell walls relax

Now knowing that dilation occurs when cell walls relax and dilation is often uncomfortable, choose the best answer.


 

        when cell walls relax 