D) He was the head of the Freedmen'd Bureau.
A planetary nebula is a (ring-shaped) type of nebula formed by an expanding shell of gas around an aging star. *a planetary nebula is a type of nebula*. im not completely certain though. i might be wrong.
For number 17, the city with the highest polulation density is Tokyo. Most of Japan's people live there.
This is true!! hope this helps. :)
