The completed sentences are:
- This type of graph is called a \( \text{scatter plot} \).
- The Water Index is plotted on the \( x \)-axis.
- The percentage of people with access to food is plotted on the \( y \)-axis.
Thus, the final answer is:
\[
\boxed{
\begin{align*}
- & \text{ This type of graph is called a scatter plot.} \\
- & \text{ The Water Index is plotted on the } x\text{-axis.} \\
- & \text{ The percentage of people with access to food is plotted on the } y\text{-axis.}
\end{align*}
}
\]