Task: Text Categorization
Input (English): Question: The papillary muscles: 
 Options:  <0> They contract atrio-ventricular valves. <1> They prevent the reflux of blood to the atria. <2> They avoid the eversion of the semilunar valves. <3> They form the interventricular septum. <4> They are formed by visceral smooth muscle.
Output (English): biology