Answer
Refer to Graph I
Domain is all real numbers of $x$
Range is {$y$ | $y \ge 4$}
The graph is a graph of function
Work Step by Step
Refer to Graph I for the graph of $y$ = $x^2$ + 4 (in black color).
The domain is all real numbers of $x$, and
the range is {$y$ | $y \ge 4$}.
By means of vertical line test (in red color), the graph is a graph of function since at any x-value, there is no more than one y-value.
