Because vaccines have healthy viruses that try to get your body to be immune to the diseases so when you are already sick your body won't respond to the vaccine because it's just more viruses
It is B , I know this thanks to the fact I took PE and our teacher teach us about the body !
Answer:
the threat to/of one's life and property
1. Infected needles
2. Insect bite
3. Organ transplant
4. Blood transfusion