2. All living things on the earth come from the ocean. From the cellular level, life activities need salt. Cells with less salt absorb water and more cells dehydrate salt to regulate the water circulation in the body.

Primitive people ate salt. Salt can be obtained from animal food or from stones, and many herbivores will punch in the stones that produce salt.

4. The natural formation of human civilization, from settlements to cities, mostly has the same characteristics, relying on two key resources, one is fresh water and the other is salt. The main traffic routes are basically built for transporting salt, and even at the expense of transporting salt by river. Buy buy of ancient western salt must be paid by gold, and China still strictly controls salt from salt tax to official salt. Salt used to be a strategic material, which is extremely important.

5. Salt has a neglected feature-addiction. As a necessity of life, salt is also a rare material. When people eat salt, the brain will give rewards as encouragement for correct behavior. So I am very happy to eat salt, and I still want to eat it.