What do vaccines simulate the production of?

Vaccines are diluted germs that are injected or otherwise introduced into the body. As a result of getting a vaccine, the person will be protected from developing the disease at a later date

Explanation:

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.