True, communication most noticeably so. Transport has too
Answer:
The Galactic Center (or Galactic Centre) is the rotational center of the Milky Way galaxy; it is a supermassive black hole of 4.100 ± 0.034 million solar masses, which powers the compact radio source Sagittarius A*.
a. large-mass stars
This is because they take longer to burn out.
I think d all of the above