Which descriptive statistic would a researcher use to describe how close a student's sat score is to a school's average sat score?

I believe the answer is: Standard deviation

Standard deviation refers to the amount of value that deviate from the mean/average from the rest of the group. This deviation is often used to highlight the  'high-end'  and  'low-end' of the group.  This signify the difference in inherent characteristics within the subject.

the allies overtook outlying islands to make access to japan easier.