stems curling in response to touch stems swelling in response to water flowers opening in response to light roots growing in response to gravity
A morning glory is a type of flowering vine that climbs trees and fences. Which of the following behaviors most helps a morning glory plant climb a fence?

Options:
- stems curling in response to touch
- stems swelling in response to water
- flowers opening in response to light
- roots growing in response to gravity

stems curling in response to touch