When narcoleptics fall asleep, they often go directly into __________

In regard to the way rods and cones operate, ______

a. neither rods nor cones pool their signals on the 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. both cones and rods tend to pool their signals on their way to bipolar cells

Hard to manipulate variables, such as age or gender, are considered __________ independent

variables. Fill in the blanks with correct word