Step-by-step explanation:
From year 1 to year 2, the plant grew 1.5cm in the one year span.
However from year 4 to year 5, the plant grew 6cm in the same one year span.
This tells you that a linear model would not be appropriate for the data (fluctuating changes in the same time span)
Rather, a quadratic or exponential model would best fit the data. (C)
