When the human body mobilizes its defenses against a pathogen the body recognizes the pathogens?

The body recognizes after the body has been presented with or dealt with the pathogen before. the immune system defends against pathogens and the immune system then after recognizes the pathogen when the pathogen has been killed. the pathogen is recognized through the proteins presented on its surface. vaccinations contain pathogens but in small amounts in which the body can control and defend against, after the body has killed the pathogens it will later recognize it and defend better

The salt in the sea water dehydrated the sailor because her body could not take in the amount to salt in the sea water