The graph is a function. When drawing a vertical line, there will be two circumstances:
The line intersects only one point on a graph.
The line intersects more than one point on a graph ( POI > 1 )
For the first circumstance, the graph that has only one intersect with a line - it is a function. For the second circumstance, the graph cannot be a function as it gives more than one y-value for a single x-value.
The conclusion is that if a line only has one intersect on a graph then it is a function. Otherwise, not a function but a relation instead. All functions are relations, but not all relations can be functions.
Answer
The graph passes the vertical line test and is a function.
