what are the parts of a smooth line graph?

Answer 1

If smooth you mean a straight line graph:

It follows the equation y=mx + c

y = whatever is on the y-axis
x = whatever is the x axis
c = the intercept(crossing point) the line makes with the y axis (x is zero)
m = the gradient of the line (y distance/ x distance)

Answer 2

Um...the x-axis, the y-axis and the line.