The correct answer is - C. The river carried enormous amounts of silt.
The Yellow River, got this nickname because it is yellowish from the enormous amounts of silt it carries. When there were heavy rains, or the snow was melting, the river got more water, but also more silt, so the silt was partially blocking the free movement of all of the water, so it was flooding the surrounding are. In one way, the floods were terrible because they were destroying pretty much everything on their way, but on the other side, were living huge amounts of deposits that were fertilizing the soil for the agriculture.
the answer to this question is A
The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken up into tectonic plates. The Earth's lithosphere is composed of seven or eight major plates (depending on how they are defined) and many minor plates. Where the plates meet, their relative motion determines the type of boundary: convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The relative movement of the plates typically ranges from zero to 100 mm annually.[2]
Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the lithosphere remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories, since disproven, proposed gradual shrinking (contraction) or gradual expansion of the globe.[3]
Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.
B. An atoms energy level doesn’t have the maximum number of electrons.
Atoms bond in order to film their outer energy shells.
