The Correct Answer is Option 'C' - Osmosis

Osmosis is the process by which roots of plants absorb water from the soil. It is a type of passive transport that occurs across a semi-permeable membrane. Let's understand this process in detail:

1. What is Osmosis?
Osmosis is the movement of solvent molecules (in this case, water) from an area of lower solute concentration to an area of higher solute concentration through a semi-permeable membrane. The semi-permeable membrane allows the passage of water molecules but restricts the movement of solute particles.

2. Role of Roots in Water Absorption
The roots of a plant have tiny hair-like structures called root hairs that increase the surface area for water absorption. These root hairs are in direct contact with the soil particles and create a concentration gradient between the soil solution and the root cells.

3. Concentration Gradient and Osmosis
When the soil is moist, it contains a higher concentration of water compared to the root cells. This creates a concentration gradient, with the soil solution having a higher water potential. The root cells, on the other hand, have a lower water potential due to the presence of solutes in their cytoplasm.

4. Osmotic Pressure
The difference in water potential between the soil solution and the root cells creates an osmotic pressure. This osmotic pressure drives the movement of water from the soil into the root cells through osmosis.

5. Selective Permeability of Cell Membrane
The cell membrane of the root cells acts as a semi-permeable membrane that allows the passage of water molecules but restricts the movement of solute particles. This ensures that only water molecules enter the root cells, while the solutes remain in the soil solution.

6. Water Transport in Plants
Once water enters the root cells through osmosis, it moves from cell to cell through the root cortex via the apoplast and symplast pathways. Eventually, it reaches the xylem vessels, which transport water and dissolved minerals upwards to the rest of the plant.

In conclusion, the roots of plants absorb water from the soil through the process of osmosis. Osmosis allows water molecules to move from an area of lower solute concentration (soil) to an area of higher solute concentration (root cells) through a semi-permeable membrane. This process is essential for the survival and growth of plants.