Match the key aspect of a functions graph with its meaning.

Answer:
1 - C
2 - A
3 - D
4 - B
Step-by-step explanation:
Consider an arbitrary function y=f(x).
1. f(x)>0 means y>0. y>0 determines all points on the graph which have positive y-coordinates. Positive y are corresponding to those x from the domain, for which graph lies above the x-axis. So 1 - C
2. f(x)<0 means y<0. y<0 determines all points on the graph which have negative y-coordinates. Negative y are corresponding to those x from the domain, for which graph lies below the x-axis. So 2 - A
3. To find y-intercept, we have to substitute x=0, so input is zero. Hence, 3 - D
4. To find x-intercept, we have to substitute y=0, so output is 0. Hence, 4 - B