Final answer:
In Washington, D.C., Ward 7 and Ward 8 have the highest percentage of black residents and the lowest life expectancy.
Step-by-step explanation:
In Washington, D.C., the Wards with the highest percentage of black residents are Ward 7 and Ward 8. These Wards have historically had a predominantly black population. On the other hand, the Wards with the lowest life expectancy are also Ward 7 and Ward 8. These Wards have faced challenges related to poverty, limited access to healthcare, and other social determinants of health that contribute to lower life expectancy.