A biologist wants to know whether a local population of scrub jays has ever experienced a bottleneck. Which of the following should she do?
A. Observe the population to see whether it is increasing or decreasing in size.
B. Check the historical records to see if the birds were hunted in the past.
C. Observe the population to see if they interbreed with the neighboring populations.
D. Test the population's genetic diversity by sequencing the genome of all individuals.
