A natural remedy for healing sore throats is to gargle with salt water. Use what you know about passive transport to explain why this remedy works.

The thing that is happening when you gargle with salt water is you are creating a high-salt barrier. As a result fluids are pulled out from the tissues in the throat area and the viruses are washed out. Fluids (water) are moving down the concentration gradient (to the area with the high salt concentration) and this is an example of passive transport.