According to the given graph, we have the following:
1) The graph represents a plane descending.
2) The line is slanting downwards and therefore has a negative slope.
3) It takes the plane 15 seconds to touch the ground.
4) The plane starts at 3 kilometers in the sky.
5) Graph does not touch the origin (0,0).
The given graph shows a decreasing line, starting at y = 3, and reaching y = 0 when x = 15.