Task: Text Categorization
Input (English): Question: The chemosmotic theory: 
 Options:  <0> It was proposed by Singer and Nicholson. <1> Explains the mechanism of phosphorylation at the substrate level. <2> It requires that the membranes in which it forms are closed compartments. <3> It does not explain the synthesis of ATP in photosynthesis. <4> It has nothing to do with redox reactions.
Output (English): biology