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.

answer; hypnagogic sensations)

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.