government systems

https://www.youtube.com/watch?v=KFXuGIpsdE0 (republic vs democracy vs oligarchy vs monarchy vs oligarchy)

https://www.youtube.com/watch?v=4quK60FUvkY&spfreload=5  (parliamentry vs presidential democracy)

https://www.youtube.com/watch?v=JpVv49v8BLQ  (capitalism, communism, socialism)