instruction:
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:
Question: The denaturing of proteins: 
 Options:  <0> Alters the native conformation without affecting the biological activity. <1> It is always irreversible. <2> It can only be achieved by treatment with strong acids. <3> It does not affect the primary structure. <4> It produces the hydrolysis of the protein.
answer:
biology


question:
Question: A 71-year-old man presented with severe pancytopenia without any immature cells and with a medullar study suggestive of severe aplastic anemia. What would be the fundamental therapeutic approach? 
 Options:  <0> Treatment with methylprednisolone at a dose of 1 g / Kg / day for 5 days. <1> Study of siblings and if any is HLA compatible, allogeneic transplant of hemopoietic progenitors. <2> Immunosuppressive therapy with cyclosporine and antitimocitic immunoglobulin. <3> Hemotherapeutic support. <4> Chemotherapy and if autologous transplant response of hemopoietic progenitors.
answer:
medicine


question:
Question: Cardiac output decreases the increase of: 
 Options:  <0> The volemia. <1> The venous return. <2> Vagal activity. <3> The end-diastolic volume. <4> The myocardial contractility.
answer:

biology