The table is
\| \
Domain \ | \
\
Range \ | \
| \
| \
\
| \
| \
| \
\
1 \ | \
| \
0 \ | \
\
2 \ | \
| \
3 \ | \
\
1 \ | \
Express the relation as ordered pairs 
The domain of the relation is the set of all first (x-coordinates) coordinates.
\The domain of the relation is
.
The range of the relation is the set of second (y-coordinates) coordinates.
\The range of the relation is
.
Each element of the domain is paired with exactly one element of the range.
\Therefore the relation is a function.
Yes.