You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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: A distension is defined as: 
 Options:  <0> Soft tissue injury. <1> Forced movement of abrupt production. <2> Injury by stretching a muscle. <3> Injury of the joint capsule. <4> Interruption in the continuity of a bone.
Solution: nursery
Why? Distension means Bloating and swelling in the belly area. It does not have much to do with chemistry, psychology, pharmacology, biology and medicine. Hence, the correct topic is nursery.

New input: Question: With regard to pyrogens and biotechnological medicines, it is possible to say: 
 Options:  <0> They have no tendency to aggregate or form large units with high molecular weight. <1> Ion exchange chromatography procedures (using their positive charge) can reduce endotoxin levels. <2> Ion exchange chromatography procedures (using their negative charge) can reduce endotoxin levels. <3> Ion exchange chromatography procedures (regardless of their charge) can reduce endotoxin levels. <4> They are unstable under standard autoclaving conditions.
Solution:
pharmacology