How does the book animal farm by george orwell relate to the word microcosm?

Animal Farm is a microcosm of Russia and the events surrounding the 1917 revolution in that country. A microcosm is a small-scale replica of something - not usually an exact replica, but close enough that you can see the similarities. Most of the characters represent a real person in Russia; most of the events in the book are similar to something that really happened in Russia.