Task: Text Categorization
Input (English): Question: It is characteristic of the alpha helix: 
 Options:  <0> Present 3.6 amino acid residues per turn. <1> Be levorotatory <2> Be stabilized by intrachain disulfide bridges. <3> Present ionic bonds between amino and ketone groups loaded with peptide bonds. <4> Have the side chains of the amino acids inwards.
Output (English): biology