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 non-selective medium commonly used for the growth of gonococcus (Neisseria gonorrhoeae) is: 
 Options:  <0> Chocolate agar. <1> Agar blood. <2> Mannitol saline agar. <3> Nutritious agar <4> MacConkey agar.
answer:
biology


question:
Question: By means of the angular methods used to evaluate the flow properties of a powder, it is determined: 
 Options:  <0> The ease with which the solid sets in motion. <1> The angle of repose. <2> The flow velocity <3> The resistance to displacement. <4> The density of the powder.
answer:
pharmacology


question:
Question: Acetylation of histones affects transcription: 
 Options:  <0> Blocking the incorporation of other components of the transcription machinery. <1> Preventing the remodeling of chromatin. <2> Facilitating the action of helicases. <3> Decreasing sensitivity to nuclear receptors. <4> Reducing the affinity of histones for DNA.
answer:

chemistry