1a)Facts :Tetanospasmin is a protein Integration and analysis : Integration and Analysis: Proteins are too large to cross cell membranes by mediated transport . Therefore , tetanospasmin must be taken up by endocytosis . [ page :152].1b) Facts: Movement of substances from the axon terminal to the cell body is called retrograde axonal transport .[page : 252].Integration and Analysis: Tetanospasmin is taken up by endocytosis ,so it will be contained in endocytotic vesicles . These vesicles “walk” along microtubules through reterograde axonal transport .