Answer:
1)yes the graph is a function,because it follows the 1 line rule.
2)The graph has a maximum, The graph is opened downward, which means its a maximum
3) the graph is increasing at (-2,0) and (2,0), because the graph starts to widen
4) the graph decreases at (0,4), because the graph ends there
5) the graph is linear because, because it follows the 1 line rule.
I hope this helps you :)