Two atoms that contain the same number of protons but different neutrons are isotopes of the same element.their masses are different but they react the same way chemically
Answer:
Exposure to the disease
Explanation:
Before vaccines, the only way to develop immunity to a disease was to be exposed to the disease-causing pathogen without being harmed by it. A good example of this is smallpox, which was also the first vaccine developed. It was noticed that milk maids weren't catching and dying from small pox like everyone else, because they had been exposed to cowpox. This premise was used to create the first vaccine.
Vaccines give you immunity by injecting you with a small amount of a (usually inactive) pathogen. inside your body. This means your immune system produces antibodies against it. Similar to what happened with the milkmaids.
CAM (Crassulacean acid metabolism) plants
Take a dna test... he will be more confident about it then
