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

Fact 2: Molecules are a group of atoms.

Given the two facts above, answer the question "what type of antigens does the immune system recognize as foreign to the body?" with the following options: 
- animals
 - epidermal
 - Allergies
 - negative
 - dangerous
 - graptolites
 - group of atoms
 - homogenous


 

       group of atoms  