Fact 1: Antigens are molecules that the immune system recognizes as foreign to the body.

Fact 2: Bodies are physical entities.

Given the two facts above, answer the question "What are molecules that the immune system recognizes as foreign to the physical entity?" with the following options: 
- bacteria
 - proteins
 - antibodies
 - Allergies
 - negative
 - immunities
 - parasites
 - antigens


 

        antigens 