Task: Text Categorization
Input (English): Question: About free radicals: 
 Options:  <0> They are compounds that contain two or three unpaired electrons in an outer orbital. <1> Reactive oxygen species (ROS) in the cell are only generated enzymatically. <2> Hydrogen peroxide is the most damaging radical in the cell. <3> The hydroxyl radical originates non-enzymatically (Heber-Weiss reaction) and damages proteins and DNA. <4> Oxygen is a triradical.
Output (English): chemistry