Q: In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Question: Which of the following answers is true about the HLA molecules?
Options: <0> They are very polymorphic nuclear proteins. <1> They are divided into molecules of class IgG, IgA and IgM. <2> They join peptides and present them on the cell surface. <3> They interact with cytokines to modulate the immune response. <4> They are monomorphic.
A:
medicine