The number $N$ of threatened and endangered species in the U.S. from 1993 to 2002 is approximated by the model $N = \frac{42.58t^2 + 690}{0.03t^2 + 1}$, where $t$ represents the year, with $t=3$ corresponding to 1993.
a. Use the model to estimate the number of threatened and endangered species in 2008.
b. According to the model, in the long run (several years into the future), what will be the maximum number of threatened and endangered species. Explain how you found your answer.