The human digestive system can fail if you eat something harmful, and it can break down nutrients, techinically the digestive system can stop working if you get something like Gastoparesis, which stops the movement of food through the digestive system.
The activation energy of a given chemical reaction is the minimum required amount of energy needed to start the reaction, for the reaction to start. All reactions have an activation energy, even spontaneous ones, ones that do occur spontaneously. It is a thermodynamic barrier that separates the amount of energy reactant molecules must possess to ultimately react with each other to produce the respective products.
What is risbi? First of all
The stomach <span>walls have a lining that contains epithelial cells that have a protective layer of mucus and bicarbonate. The mucous is pretty much the same stuff which lines our throat and nose.</span>