Fill in the blanks, using either affect or effect.
a.* The amount of overtime and the time of day had a significant __________ on accidents in the workplace.
b.* The amount of overtime and the time of day significantly __________ accidents in the workplace.
c. Curiously, the amount of experience does not seem to __________ the productivity of these workers.
d. Curiously, the amount of experience does not seem to have an __________ on the productivity of these workers.