Regarding the way rods and cones operate, ________

a. both cones and rods tend to pool their signals on their way to bipolar cells
b. rods, but not cones, tend to pool their signals on their way to bipolar cells
c. cones, but not rods, tend to pool their signals on their way to bipolar cells
d. neither rods nor cones pool their signals on the way to bipolar cells

Answer: b