Question

how does osmosis take place in roots ?

Answer 1

Osmosis is defined as the movement of water across a semipermeable membrane from a solution where water concentration is high to a solution where water concentration is low.
Roots of plants are plant organs made up of cell. The cell membranes of root cells act as a semi permeable membrane. The roots solution has high concentration of salt in them and low water concentration whereas soil surrounding the root has comparatively higher water concentration and low salt concentration as roots actively absorb salt from soil.
This difference in water concentration allows water to move from soil into roots across semi permeable membrane. Thus, osmosis takes place in roots due to differential concentration of salt in roots and soil.