Answer:
a zero slope is just a straight line either on the y axis or x axis but its just basically a slope of a horizontal line the never changes
example:
y-axis (1,2,3,4,5,6,7,8,9)
x-axis (2,2,2,2,2,2,2,2,2)
or
x-axis (1,2,3,4,5,6,7,8,9)
y-axis (2,2,2,2,2,2,2,2,2)