Biology The formula $w=w_{0} N^{-a}$ is a mathematical model used by plant biologists (see Shainsky and Radosevich $^{23}$ ), where $w$ is the plant size, $w_{0}$ is the maximum plant size in absence of competitors, $N$ is plant density, and $a$ is a positive constant. According to this formula, for what values of $N$ is plant size decreasing? Sketch a possible graph.