Answer
a) Increasing from $0\leq x \leq25$. Decreasing from $25\leq x \leq 50$.
b) Max population was in 1975, and it was 50,000.
c) The net change is zero.
Work Step by Step
a) From 1950 onward, the population increased greatly, but fell dramatically after 1975.
b) The population of 50,000 is the highest point on the graph.
c) Both years had a population of 40,000. While there may have been an increase in 1975, and an onward decrease, the net change is still zero.