Caswell started studying how the number of branches on his tree grows over time. The relationship between the elapsed time $t$, in years, since Caswell started studying the tree, and the number of its branches, $N(t)$, is modeled by the following function: ###$N(t)=15\cdot (1.64)\^{\Large \frac{t}{3.4}}$ **Complete the following sentence about the rate of change in the number of branches.** Every [[☃ numeric-input 1]] years, the number of branches increases by an additional $64\%$.