You have two tubes: Tube A and Tube B. Tube A has 110 mm Hg at one end and 80 mm

A. There would be no difference in flow because the pressure difference in Tube A and Tube B is the same (30 mm Hg).
B. Water through Tube B because water has a lower viscosity than a milk shake. Resistance is directly proportional to viscosity. Flow is inversely proportional to resistance. Therefore, decreased viscosity = decreased resistance = increased flow.
C. No changes because flow is equal in (A.).
D. You can change the parameters that would reduce resistance to flow. You could make Tube A shorter or increase its radius. Changing the radius would have a greater impact on increasing flow (Poiseuille's Law).