Earth is just one of the planets that revolve around the Sun in the Solar System, and 5
the Sun is just one of billions of stars within the Milky Way Galaxy. The Milky Way is
one of thirty galaxies in a cluster of galaxies called the Local Group. The local group
is just one cluster within a super-cluster called the Virgo Super-Cluster. And finally
the Virgo Super-Cluster is just a tiny part of the entire Universe. Galaxies are systems
of stars, gases, and dust that exist in a wide variery of shapes and sizes. The simplest
classification scheme devised by Edwin Llubble recognizes four basic types of
galaxies: elliptical, spiral, barred spiral, and irregular. Identify the shape of Earth's
galaxy:
A)spiral galaxy
B)lenticular galaxy
C)elliptical galaxy
D)irregular galaxy