How did Alexander the Great impact the Middle East, Central Asia, and parts of India?

English is my second language I need you use simple words in my paper. thank you
Short Essay
Choose two short essay questions. Answer in 12 sentences.
How did Alexander the Great impact the Middle East, Central Asia, and parts of India?
Why did the Eastern Roman Empire fare better against invaders than the Western Roman Empire?
What is legalism? How was it successful? Why did it not persist?