The organs of the digestive system work together to digest food and absorb nutrients.(the gastrointestinal tract organs and pancreas, liver, gallbladder, salivary glands). The circulatory system is in charge of taking those nutrients and delivering them to our cells.
The substance that must come through the cell membrane for the cell to live is nutrients. Cells would die if they did not get nutrients. Nutrients are what keeps the cell running.
No because if your body has never experienced it before it will not no what to do and most likely the body will just send out/produce the other common antibodies or cells