#### Answer

$D:[0,\infty)$
$R:(-\infty,1]$

#### Work Step by Step

Domain (D) is the set of all possible input values of the function.
The function $f(x)=1-\sqrt x$ is defined for all non-negative values of x.
Domain of $f(x)=1-\sqrt x$ :
Solution: $ x\geq0$
Interval notation:$[0,\infty)$
Range (R) is the set of all values of the function f(x) as x varies throughout D.
x varies through D:$[0,\infty)$
Range of $f(x)=1-\sqrt x$ :
Solution: $f(x)\leq1$
Interval notation:$(-\infty,1]$