Oedema, or swelling, occurs when fluid accumulates in the body's tissues. This can happen due to various reasons, including prolonged sitting, which can reduce blood and lymph flow, leading to fluid buildup.
Soaking the feet in warm salt water can help reduce this swelling. The warmth of the water increases blood flow, while the salt (sodium chloride) in the water helps draw fluid out of the tissues.
Analyzing the Options
- (A) Reverse Osmosis
Reverse osmosis is a process where water is forced through a semipermeable membrane to remove contaminants. This is not the mechanism by which salt water reduces swelling. - (B) Osmosis
Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. The salt in the water increases the solute concentration outside the cells, drawing water out of the cells and reducing swelling. - (C) Edema
Edema is the condition of swelling, not the process by which it is reduced. - (D) Diffusion
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. While diffusion plays a role in many biological processes, it is not the primary mechanism by which soaking in salt water reduces swelling.
Conclusion
The correct answer is (B) Osmosis. Soaking the feet in warm salt water reduces swelling by increasing the solute concentration outside the cells, which draws water out of the cells through osmosis.