Task: Text Categorization
Input (English): Question: The action potential starts in the membrane of the initial segment of the axon by: 
 Options:  <0> Be the place where the synapse occurs. <1> Have a higher excitation threshold. <2> Present high concentration of voltage-dependent channels. <3> Present Na + channels regulated by ligand <4> Start there the axon myelin sheath.
Output (English): biology