Lin's elevation decrease between 7:00 a.m. and 2:00 p.m.
It changes from 10 m the ground to 2 m below the ground at that interval.
How the elevation of Lin change the interval of times.
From the graph
At 7.00 a.m the elevation of Lin is 10 m. This is corresponds to the y- value when x = -5
Since the negative values of x represent times earlier than noon.
If 0 = noon
-1 = 11.00 a.m
-2 = 10.00 a.m
-3 = 9.00 a.m
-4 = 8.00 a.m
-5 = 7.00 a.m
At this value on the horizontal y = 10 m
In the positive side
1 = 1.00 p.m
2 = 2.00 p.m
At this value of x, y-value is -2
This means he is 2 m below sea level.
His elevation moves from 10 m above the ground at 7.00 a.m to 2 m below the ground level at 2.00 p.m.
so, his elevation decrease at that interval.
C complete question