This is a galaxy with a characteristic pinwheel shape with a flat disk, central bulge, and graceful arms containing regions where young stars form

A spiral galaxy.

Explanation:

This is a class of galaxy described in 1936 by the American astronomer Edwin Hubble.

The central bulge is characteristic of this type of galaxies, where the major concentration of stars resides. The "arms" are very bright and are full of young, blue stars.

The pinwheel shape is why we can easily recognize them from the earth. Astronomers think that more than 60% of the galaxies in the universe are spiral-like.

doctrine that the us had the right to expand throughout north america.

answer(c) carved on a babylonian clay tablet that showed earth as a flat circular disk;