Measurements taken of the stem of a young tree showed that its diameter changed a little. It became smaller in the daytime and larger at night. Which statement accounts for these observations?
- ADuring the day, cohesion between water molecules and lignin in the walls of the xylem vessels pulls the walls of the vessels inwards.
- BDuring the day, the tension developed in a moving column of water molecules reduces the pressure inside the xylem vessels, so that their walls move inwards.
- CDuring the night, the adhesion of water molecules to the lignin in the walls of the xylem vessels pushes the walls of the vessels outwards.
- DDuring the night, the pressure of the column of water molecules adhering to one another increases and pushes the walls of the xylem vessels outwards.