Fact 1: Dilation occurs when cell walls relax.

Fact 2: Cell wall is the rigid structure that surrounds the plant cell.

Given the two facts above, answer the question "What happens before the rigid structure that surrounds the plant cell dilates?" with the following options: 
- It decreases
 - competition
 - air cools
 - relaxation
 - cracking
 - sweating
 - rapid expansion
 - It expands


 

    relaxation     