#### Answer

The given relation defines $y$ as a function of $x$.
domain: $(-\infty, +\infty)$
range: $[0, +\infty)$

#### Work Step by Step

Note that for every value of $x$, the equation $y=x^2$ gives only one value of $y$.
This means that every $x$ is paired with only one value of $y$.
Thus, the given relation defines $y$ as a function of $x$.
The value of $x$ can be any real number so the domain is $(-\infty, +\infty)$.
The value of $x^2$ is zero or higher.
Thus, the range is $[0, +\infty)$ .