Is a horizontal or vertical line linear and/or a function?

Question

Is a horizontal or vertical line linear and/or a function? I have a graph and am unaware how to solve it.

PLEASE SOLVE FAST!!!

Answer 1

vertical line test fails the vertical line test, so Not a function. Irony

horiizontal line passes the vertical line test so its a function

but both are linear

"line" is literally in "linear" 1st 4 letters in each spell line