how does water rise from the roots of a tree to the very top?

Water rises from the roots of a tree to its very top primarily through a process driven by transpiration, cohesion, adhesion, and root pressure. The key mechanism is transpiration: water evaporates from tiny pores (stomata) in the leaves, creating a negative pressure (tension) in the leaf's xylem (water- conducting tubes). This tension pulls water upward in a continuous column from the roots through the xylem vessels all the way to the leaves. Water molecules stick together by cohesion and adhere to the walls of the xylem tubes by adhesion, maintaining this unbroken water column despite gravity. Additionally, root pressure, created by osmotic uptake of water from the soil into root cells, helps push water upward, especially at lower heights. Capillary action, the tendency of water to rise in narrow tubes, also aids water movement but is a minor force relative to transpiration pull. In summary, the combination of transpiration pull (negative pressure created by evaporation in leaves), cohesion and adhesion of water, root pressure (osmotic pushing), and capillary action work together to move water from roots to the highest parts of tall trees, sometimes hundreds of feet above the ground.