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.
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Question: Question: Form B of DNA: 
 Options:  <0> It is formed by a double helix levorotatory with two antiparallel nucleotide chains. <1> It is wider and longer than form A. <2> It has pairs of nitrogenous bases perpendicular to the axis of the helix. <3> Corresponds to dehydrated DNA. <4> It is the minority form presented by DNA under physiological conditions.

Answer: chemistry


Question: Question: The presence of nonspecific prodromes in a psychotic disorder: 
 Options:  <0> It refers to one of the three phases in which a psychotic episode evolves. <1> It refers to the acute phase. <2> It refers to the recovery phase. <3> It defines the abrupt onset of the first psychotic episode. <4> It is a phase in which the patient does not need treatment.

Answer: nursery


Question: Question: It is very common the use of rotary valves of 6 doors or routes, alternately switchable, for the injection of samples in liquid chromatography of high resolution. Which of the following answers is correct? 
 Options:  <0> In the injection position, the mobile phase flow is maintained towards the column without passing through the loop. <1> In the loading position, the loop in charge of housing the sample remains open to the atmosphere whereby the sample can be deposited by means of a syringe. <2> In the loading position, the mobile phase flow is maintained towards the column by previously passing through the loop. <3> In the loading position, the sample is inserted into the column without disturbing the moving phase step towards the loop. <4> In the injection position, the entire internal volume of the loop is directed to the waste while the mobile phase carries the sample.

Answer:
chemistry