Several studies have found that gargling several times a day with warm salt water can reduce swelling in the throat and loosen mucus, helping to flush out irritants or bacteria. Doctors generally recommend dissolving half a teaspoon of salt in one cup of water.
Daily stimulation makes us use out muscles, and if we use them daily, we can practice them. It's like using something that you haven't used in a while, it gets hard to bend or whatever over time when we don't use it, it may break into pieces, but if we use it daily, we exercise the muscles so they don't "get hard and break".
1. More genetic variation species
2. Children different from parents
3. Able to produce more offspring because of mate