Fact 1: Dilation occurs when cell walls relax.

Fact 2: Dilation is often uncomfortable.

Given the two facts above, answer the question "when is it often uncomfortable?" with the following options: 
- at room temperature
 - Plant growth is reduced
 - cloudy and rainy weather
 - pillows
 - heat or cold
 - sleeping
 - Riding a bike
 - when cell walls relax


 

        when cell walls relax 