Task: Text Categorization
Input (English): Question: The urea cycle: 
 Options:  <0> It involves the degradation of urea. <1> It was proposed by Hatch and Slack. <2> It contains a reaction that transforms citrulline into ornithine. <3> It is intimately linked to glycolysis. <4> It begins with the formation of carbamylphosphate.
Output (English): chemistry