Final answer:
After applying the exponential decay formula, the population of animals after 5 years with a 15% annual decrease from an initial population of 210 animals is approximately 93, suggesting an error in the given options.
Step-by-step explanation:
The correct answer is option b. To calculate the animal population after a certain number of years given a percentage decrease, we can use the formula for exponential decay: P(t) = P0 * (1 - r)^t, where P(t) is the population at time t, P0 is the initial population, r is the rate of decrease, and t is the time in years. In this case, the initial population is 210 animals, the rate of decrease is 15%, or 0.15, and the time is 5 years. So after 5 years the population would be:
P(5) = 210 * (1 - 0.15)^5
P(5) = 210 * (0.85)^5
P(5) = 210 * 0.4437053125
P(5) ≈ 93.178
Since we cannot have a fraction of an animal, we round to the nearest whole number, which results in approximately 93 animals. As this is not one of the given options, we can conclude that there must be a mistake in the question or the options provided.