Answer
Domain: $(-\infty,\infty)$
Range: $(-\infty,4]$
Work Step by Step
$h(x)=4-x^{2}$
This function is defined for all real numbers, so its domain is $(-\infty,\infty)$
This function represents a parabola of vertex $(0,4)$ and it opens downwards, so its range is formed by all the numbers smaller than $4$, including it, or $(-\infty,4]$