Task: Text Categorization
Input (English): Question: If the arterial pO2 decreases to 60 mm of Hg: 
 Options:  <0> Decreases ventilation. <1> Central chemoreceptors are activated. <2> The central chemoreceptors are depressed. <3> The arterial chemoreceptors are activated. <4> It produces loss of consciousness.
Output (English): biology