Carbon-14 is a radioactive substance that decays over time. One of its important uses is in dating relatively recent archaeological events. In the following table, time t is measured in thousands of years, and C = C(t) is the amount, in grams, of carbon-14 remaining.

t = Thousands of years C = Grams remaining 0 9 5 4.92 10 2.68 15 1.47 20

0.80

(a) What is the average yearly rate of change of carbon-14 during the first 5000 years? (Round your answer to six decimal places.) g/yr (b) How many grams of carbon-14 would you expect to find remaining after 2005 years? (Round your answer to two decimal places.) (c) What would you expect to be the limiting value of C?