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: Which of the following statements is correct regarding the epidemiology of mood disorders ?: 
 Options:  <0> Bipolar disorders account for 25-30% of all mood disorders. <1> The average duration of a depressive episode is usually about 2-3 months. <2> The percentage of relapses of depression throughout life is estimated at 75%. <3> The risk of suicide in depressive disorder is greater than bipolar disorder. <4> 50% or more of the history of bipolar disorder is found in the families of patients with depression.
psychology

Question: Controls the passage of substances to the central nervous system: 
 Options:  <0> Meninges. <1> Choroid plexus. <2> Hemato-encephalic barrier. <3> White substance <4> Schwann cells and oligodendrocytes.
biology

Question: What is the PCNA or nuclear cell proliferation antigen? 
 Options:  <0> It is a protein that prevents the double helix from forming in the replication bubble. <1> It is a protein that increases the ability to replicate long fragments of eukaryotic DNA polymerase. <2> It is the protein responsible for the elimination of positive superhelices. <3> It is the typical conformation of the DNA double helix in eukaryotes. <4> It is the enzyme responsible for copying the DNA of the telomeres.

pharmacology