Final answer:
The mark-recapture method is best used for mobile organisms and would be most appropriate for sampling a population of sharks, allowing scientists to estimate the population size and density.
Step-by-step explanation:
The mark-recapture method would be best for sampling a population of sharks. This method is suited for mobile organisms such as mammals, birds, or fish. It involves capturing a sample of the animals, marking them in a distinguishable way, releasing them back into their environment, then later recapturing a new sample to see how many marked individuals are present. This technique allows scientists to estimate the size and density of a population by using the proportion of marked to unmarked individuals in the second sample to make inferences about the total population.