Scheme

 =** Scheme: Why are galaxies flat? **=

=**-Introduction**= =*** ¿What is a galaxy? Definition**= =*** General description of a galaxy**= =**.- Size**= =**.- Forms**= =**.- Composition**= =**.- Types of galaxies**= =**.- Behavior**= =**-Why are galaxies flat?**= =**-Conclusion**=