i guess because citrate or anything citric evaporates after in an open area.
Answer:
B- Are constantly replacing themselves,
Answer:
Explanation:
Active - the process of exposing the body to an antigen. Exposing the body will generate an adaptive response that takes a few days or weeks to develop and can be life long lasting.
Passive - it is provided when we are given antibodies to disease. Instead of producing the antibodies with the immune system, they are given. Like a newborn baby acquires immunity from the placenta.
Natural - it works to fight off pathogens before they begin an active infection. Sometimes it is not enough to stop the pathogen or the pathogen exploits the immune response and gets to the cells.
Yes,because it is where the enzymes are stored
