Which of the following describes a decreasing function?

A decreasing function is characterized by a negative slope, meaning that as the input (or x-value) increases, the output (or y-value) decreases. In simpler terms, if you were to look at the graph of a decreasing function from left to right, you would observe that the points on the graph are getting lower.

When considering the correct answer, the description "the graph falls to the right" accurately captures this behavior. As you move to the right along the x-axis, the y-values diminish, showcasing a decline in output.

The other descriptions don't align with the characteristics of a decreasing function. If a graph rises to the right, that indicates an increasing function. A horizontal graph suggests that the function remains constant, which means the output does not change as the input changes, while a flat graph also signifies no change in output. Therefore, only the option that describes the graph falling to the right is consistent with the definition of a decreasing function.