To determine if the relation represented by the semicircle is a function, we can apply the vertical line test. The vertical line test states that if any vertical line intersects the graph of the relation more than once, the relation is not a function.
In the case of a semicircle, it opens either upwards or downwards, and there are points on the left and right sides of the semicircle that will vertically align with points in the middle. For example, if you draw a vertical line at \( x = 0 \), it will intersect the semicircle at two points (the left and right half of the semicircle).
Since there are vertical lines that can intersect the graph of the semicircle at more than one point, the relation is not a function.
Therefore, you should enter 2 to indicate that the relation is not a function.