Consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora.
Bacteria up to 60% of the dry mass of feces
If bacterium has 1㎛ diameter, the length of 100 trillion bacteria is about 100 thousand kilometer.
It means we can turn around the earth twice and half with these bacteria.
Functions of gu
Each person should have distinctive
character from others.
Children are able to freely express themselves especially in school
Children create their own life unaffected by life of their parents
Private information cannot be disclosed even to a family member.