Answer :
B. They produce an immune response.
Vaccines protect you by preparing your immune system to recognize and fight serious, and sometimes deadly, diseases. A vaccine contains a specific part of a germ (bacteria or virus), called an antigen. The antigen is killed or disabled before it's used to make the vaccine, so it can't make you sick.
Vaccines protect you by preparing your immune system to recognize and fight serious, and sometimes deadly, diseases. A vaccine contains a specific part of a germ (bacteria or virus), called an antigen. The antigen is killed or disabled before it's used to make the vaccine, so it can't make you sick.