What type of membrane junction would you expect to be most plentiful in the bladder? why?

The correct answer is tight junctions.

Tight junctions comprise weblike strands of transmembrane proteins, which combines with the outer surfaces of adjoining plasma membranes together to lock the passageways between the adjacent cells.

The cells of epithelial tissues, which lines the urinary bladder comprise many tight junctions to reduce the passage of components amid the cells and inhibit the constituents of these organs from seeping into the surrounding tissues and blood.