To determine if a graph represents a function, we can use the Vertical Line Test. The test works by imagining drawing vertical lines through the graph. If any vertical line crosses the graph at more than one point, then the graph does not represent a function.

In this image, we see a downward-facing curve. If we were to apply vertical lines across the graph, each vertical line would intersect the curve at exactly one point at every x-value. Therefore, this graph does represent a function.

Would you like more details or have any further questions?

Here are 5 related questions you might consider:

1. What is the Vertical Line Test, and why does it work?
2. What kind of function does this graph represent (e.g., quadratic)?
3. What are some common graphs that fail the Vertical Line Test?
4. How do domain and range relate to functions and graphs?
5. How can you determine if a graph represents a one-to-one function?

Tip: A parabola that opens upwards or downwards will always pass the Vertical Line Test and is always a function.