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.

[EX Q]: Question: The secretion of GH or growth hormone: 
 Options:  <0> It stops at 20 years old. <1> It last for ever. <2> During the day it is greater than at night. <3> It is stimulated by somatostatin. <4> It is stimulated by the substances.
[EX A]: biology

[EX Q]: Question: Indicate the net charge of an amino acid with a neutral R group for a pH value below its pI: 
 Options:  <0> Negative net charge. <1> Positive net charge. <2> Without charge. <3> It is necessary to know the exact pH value to answer this question. <4> It is necessary to know the concentration of the amino acid to answer this question.
[EX A]: chemistry

[EX Q]: Question: The cholera toxin: 
 Options:  <0> Inhibits protein synthesis. <1> It is hemolytic and dermonecrotic. <2> Alters the flow of electrolytes in the intestine. <3> It is formed by a single polypeptide that is cleaved by the effect of proteases. <4> It produces food poisoning.
[EX A]:
biology