Answer
See below.
Work Step by Step
a. Domain : The domain is the set of all $(x,y)$ satisfying $-1 \leq y-x \leq 1$ .
b. Range: $R: \dfrac{-\pi}{2} \leq z\leq \dfrac{\pi}{2}$
c. Level Curves: These are the straight lines: $y-x=c$ ; $-1 \leq c \leq 1$.
d. Boundary points is at the two straight lines $y=1+x$ and $y=-1+x$ or, $y=x-1$
e. Closed.
f. Unbounded