Question

Doctors often use certain medications to treat infections. A few people have a reaction to some of these medications, such as itching, swelling, or trouble breathing. This is an example of
1. using antibodies to cure a medical problem
2. the body's immune system overreacting to a usually harmless substance
3. the body creating a mutation to fight unknown pathogens
4. a vaccine causing the body to produce antigens against the infection

Answer 1

Number 4 the antigens fight off the infection since the body knows it is an infection