B Vaccinations protect people when they are exposed to the microorganism to which they were vaccinated. This secondary response happens when the person is exposed to the microorganism. At that time, IgG production is a lot higher, making it the main antibody class in the second response. IgM is more active when it comes to the first exposure. A lot of people who have allergies have IgE in their bodies, too. IgA is the most common secretory antibody, and it stops pathogens from attaching and invading through the mucosal membranes of the body.
The statement water is easily polluted..... is true. Water is pretty much the world's best solvent. So even toxic substances are easily dissolved in it and when that happens they pollute the water.
