The factor that helped the United States in making the inland transportation and commerce to be possible is in letter C. The intricate river system. I hope you are satisfied with my answer and feel free to ask for more if you have clarifications and questions.
Answer: Traditional economic systems
Explanation: In other words, traditional economic systems are the most basic and ancient type of economies. Large parts of the world still qualify as traditional economies, primarily rural areas of second- or third-world countries, where most economic activity revolves around farming and other traditional activities.
The falaj system in was used to transport water to farms and villages
Answer: it is the rock formed within the rocks crust.
Explanation: Rocks formed from magma are called igneous rocks. Intrusive igneous rocks form when magma cools inside the Earth. Rocks that form from magma erupting onto the Earth's surface are called extrusive igneous rocks. Extrusive igneous rocks have little to no time to crystallize and, as a result, the crystals are very small or microscopic.