Question

1.What is true about the galaxies in our Universe?
They are all the same shape
They are all the same size
They are all spread out evenly throughout space
They orbit each other in clusters

2.An Sa galaxy is best described by which of the following:
A spiral galaxy with loosely wound arms
A spiral galaxy with tightly wound arms
An irregular galaxy
A barred spiral galaxy

3.What is located at the very center of most galaxies?
globular clusters
our solar system
a black hole
a supergiant star

Answer 1

1) They orbit each other in clusters

Reason - they orbit around the common center of mass called barycenter

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2) A spiral galaxy with tightly wound arms

This is the standard description. Here S is for spiral and a is sub class. A galaxy with very tightly wound arms belongs to class a

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3) A black hole

Most of the galaxies we know have a black hole resting at the center. Our own milky way is no exception.