Answer:
The simple answer would be by, "checks and balances", is how the two branches check upon each other. However there are specific methods in doing "checks and balances," hope this helps as a starting point to your question!
The Spartans were very good in hand to hand combat. The Athens had a very successful navy. The Athens made an invention of the ships so that, under multiple people at once would row and it would have to stay in that motion. There is more but I don't know what lesson you are on...
1. Traditional Economy
2. Command Economy
3. Market Economy
4. Mixed Economy
5. Collective Farms
6. Natural Resources
7. The Military
