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 coulometric evaluation: 
 Options:  <0> You do not need the current performance to be 100%. <1> It does not need an indicator system of the end point. <2> Always use a potentiostatic system. <3> It uses a titrant that is generated electrolytically. <4> You need a burette to add the titrant.
chemistry

Question: Immunoglobulin isotype change affects: 
 Options:  <0> The constant regions of the heavy chains. <1> The constant regions of the light chains. <2> The totality of heavy chains. <3> The entire immunoglobulin molecule. <4> The hypervariable regions of the heavy chains.
biology

Question: The tube of very small diameter and about 6 meters in length that runs along the posterolateral side of the testicle and connects with the vas deferens, is it called? 
 Options:  <0> Prostate. <1> Epididymis <2> Urethra. <3> Epéndimo. <4> Seminiferous tubule.

pharmacology