Which of the following is a major force that moves water through the xylem tissues of a plant?
a. pressure-flow
b. transpiration pull
c. capillary action
d. both b and c

The correct answer will be option D (both b and c).

Explanation:

Xylem is a type of vascular tissue in plants which transport the water and minerals in plants.

The major force involved in the transport of water through xylem are :

1. Transpiration pull-The force generated by the plants due to loss of water through a process called transpiration in leaf area which aids in the suction of water and minerals from roots to other parts of the plants is known as transpiration pull.

Loss of water in leaves due to transpiration generates negative pressure potential which causes upward movement of water from soil to roots to leaves is the major driving force in transport of water.

2. Capillary action- The movement of a liquid across the surface of a solid due to adhesion between solid and water molecules is known as capillary action.

Plant transpiration causes upward movement of water through xylem to which water molecules adhere gets the water to the tips of the tallest trees.

Thus, option D- transpiration pull  and capillary action is the correct answer.