Where are the ionization nebulae predominantly located in the galaxy m51?

Hey, i was what is consisted in a sustainable city? like what unique designs they have, etc. for answering ; )

Why did the belgian parliament pass laws to decentralize its government? a. to increase trade with neighboring luxembourg b. to decrease the political power enjoyed by the flemish c. to enable belgium to join the european union d. to reduce tensions between belgium's two main ethnic groups

What is the border between layers a through f and layer g called?