Question 86101
Since the problem states:


"The scientists note that the population has
steadily decreased over a period of time"


this means that we'll have a graph that will decrease. So we can eliminate answer D right off the bat (since its increasing) and answer C (since it neither increases nor decreases). Now since it also states 

"...until the population is approximately half the number of fish
originally stocked"


So lets say we start with 10 fish, then over time, we should have 5 fish left over. So looking at answer B, we start with 5 fish (count 5 units up on the axis) and over time we level off to 3 fish. Since half of 5 is 2 and a half (which is not a clean number of fish) and we really end up at 3 (which is not half of 5) we can eliminate answer B. So that leaves answer A. Notice we start at 4 fish and over time we end up with 2 fish (which is half of 4)


So the answer is A