A biologist is studying the relationship between the mass of brains found in mammals taken from a forest and the body mass of the mammals. A sample of 14 such mammals was taken. The equation of the least-squares line for the relationship between brain mass and body mass is computed as body mass hat = 561.9 (brain mass) minus 16485. A graph titled Brain Mass versus body mass has brain mass (grams) on the x-axis, and residual on the y-axis. The points decrease, and then increase.

Based on the residual plot, is a linear model appropriate for describing the relationship between brain mass and body mass?

A linear model is not appropriate, because the residuals are not centered about zero.
A linear model is appropriate, because there is a clear pattern shown in the residual plot.
A linear model is not appropriate, because there is a clear pattern shown in the residual plot.
A linear model is appropriate, because many of the residuals are close to zero for all brain weights.