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 immersion oil used for microscopic observation: 
 Options:  <0> Protects the sample from the oxidizing effect of air. <1> Lubricate the objective lens. <2> Reduces refraction and increases resolution. <3> It acts as a lens that increases magnification. <4> Avoid dehydration of the preparation.
answer:
biology


question:
Question: A 72-year-old woman with type 2 diabetes and chronic renal failure in stage 5. If a pulmonary thromboembolism is suspected, indicate which diagnostic test would be contraindicated: 
 Options:  <0> Transthoracic echocardiogram. <1> Pulmonary scintigraphy <2> Pulmonary angioCT. <3> Electrocardiogram. <4> Chest x-ray.
answer:
medicine


question:
Question: In mammals, Toll-like receptors (TLRs) are receptors: 
 Options:  <0> Signaling. <1> Antigenic <2> Of histocompatibility alleles. <3> Of phagocytosis. <4> Of chemokines.
answer:

biology