They allow people to move easily between the countries. Also more share a common currency.
Answer: the third longest river in the world is the Yangtze river at 3,915 miles long
Explanation:
Surface of the Earth: Most of the Earth's surface (70%) is covered with water, and the remaining 30% is taken up by the seven continental landmasses. However, underneath the water that fills the oceans, and the dirt and plants that cover the continents, the Earth's surface layer is made of rock.