1 - The flow of the river may change as water is fed out into tributaries. 2- As a river flows it may etch out the river bed and create a gulley as it moves sediment and debris. 3- Depending on the speed of a stream it can form into a meandering river with twists and turns. What is interesting about these rivers is they actually move as debris is deposited on one side of the meander and picked up on the other. 4 - Depending on topography the river may increase in speed and give you rapids.
Middle America refers to the states to the south of the US and specifically Mexico, the states of Central America and Islands near Central America. Venezuela does not belong to those states; It is part of South America and it is quite far from the other areas, relative to the distance between them.
