The total number of endangered species y can be approximated by the formula

where t is the number of years past 1980.
(a) The actual numbers of endangered species for selected years were as follows.

For each of these years, find the number of endangered species predicted by the formula. Round your answer to the nearest integer.
(b) Given that there were 1037 endangered species in 2007, how many more species does the formula estimate will be added to the endangered list in the next 13 years, by 2020?
(c) Why do you think the answer to (b) is smaller than the number of species added during the 13-year period from 1990 to 2003?
(d) Why is it reasonable for a formula such as this to have an upper limit that cannot be exceeded? Use large t-values in the formula to discover this formula's upper limit.

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1095 1+ 10.12(1.212) 1990 2003 2012 1086 442 987