It's all about the volume if I'm correct. The supply and demand in each exchange is slightly if not largely different. So more demand obviously means higher price and vice versa. They are not that significant though.
Yes all coins will dependsnon the volume. And it is a game by supply and demand, if you know the concept of that then you will understand how it works, more supply means less deman, and if less supply more demands. They are inveresly proportional to each other.