Answer the following questions about functions. (10 points)
A series of points in the form (x, y) is a function if every____-value is different.
A graph is a function if a vertical line passes through the graph at most_____time.
A series of points in the form (x, y) is a function if every____-value is different.
A graph is a function if a vertical line passes through the graph at most_____time.