<span>Large changes in allele frequencies can occur in a short time.
I'm taking the test now and that's what I know.</span>
CHICAGO (Reuters) - Lab experiments on a new strain of the H7N9 bird flu circulating in China suggest the virus can transmit easily among animals and can cause lethal disease, raising alarm that the virus has the potential to trigger a global human pandemic, researchers reported on Thursday.
I believe the answer is B. They both are found in the nucleus.