A linear graph is one with a line which has the same slope throughout. In this case, you can tell that the line doesn't have the same slope all the way through because it flats and also decreases in one section.
Increasing will mean the line's slope is positive, or it tends to go upwards. The slope will be constant, 0, so it's just a horizontal line. The slope of the line will decrease is negative, and it tends to go downwards. In this case, this would mean that segment k is., as it seems to go upwards, l is constant, because it's a horizontal line, and would be decreasing because it's going downwards.
I might assume that the ant began moving away from the hole for 2 seconds, then stopped for 3 seconds, and then went back to the hole for 3 seconds again.
~s9154499~
~Mia for short~