Most, yes. All, no. The biggest westward flowing rivers are the Miño, Duero, Tajo, Guadiana, and Guadalquivir. The largest eastward flowing river is the Ebro.
Small streams flow into rivers and the rivers flow to bigger rivers.
Most rivers begin in the Appalachian mountains or rivers flow into the Gulf of Mexico.
Most Colorado rivers flow generally westward, toward the Pacific Ocean. The state is characterized by its mountainous terrain, which influences river courses to move from the Rocky Mountains downhill. However, some rivers, particularly those in the eastern part of the state, flow eastward into the Great Plains and eventually reach the Gulf of Mexico. The flow direction is largely determined by the elevation and topography of the region.
No.
Of course there are, the four most important rivers in Spain are the Duero, the Guadalquivir, the Guadiana, and the Tagus.
Southeast
Most of the rivers in the eastern United States begin in the Appalachian Mountains. This mountainous region serves as a significant watershed, where precipitation collects and flows downwards, creating numerous streams and rivers. The rivers generally flow eastward toward the Atlantic Ocean, with some rivers also flowing into the Gulf of Mexico. In contrast, many rivers in the West originate in the Rocky Mountains.
Actually many rivers run north in North America. Water has no sense of direction. If flows downhill by gravity. Most rivers east of the Rocky Mountains do flow in a southerly direction because the elevation is lower to the south and they are flowing toward the Gulf of Mexico. Source: Riverlorian.com
Mexico
the Mississippi river, Ohio river, and the missouririver are the three most important rivers in the U.S. that flow south.
Most rivers begin in the Appalachian mountains or rivers flow into the Gulf of Mexico.
Gravity, not gods cause rivers to flow. Most rivers in the northern parts of continents flow from south to north.