Answer
The domain is $(-\infty,\infty)$.
The range is $(0,1]$.
The y-intercept is (0,1).
Work Step by Step
The domain is a horizontal span from the function's smallest value of x to the function's largest value of x.
The range is a vertical span from the function's smallest value of f(x) to the function's largest value of f(x).
The x-intercepts are all points of a graph when f(x)=0 while the y-intercepts are all points of a graph when x=0. In this case, there is only the y-intercept which is:
$y=e^{-0}$
$y=1$