Every part of a tree or plant receives water and nutrition in the form of sap. This sap comes from roots. Roots absorb sap from soil. The transport of sap from roots to the various parts of plants is based on different scientific principles such as: osmotic pressure, transpiration and cohesion of water. First, water and minerals pass into the roots from the soil through osmosis* from one cell to another.
Secondly, transpiration is the evaporation of water from leaves. This process pulls water upwards from roots to leaves. This is a continuous process and these water molecules are cohesively attached with and another. Hence, the water along with the minerals keeps on moving up in plants.