It supports current flowing because when the water in the ocean heats up the current goes in a circle
The main reason for the wall's construction had always been defense. Since China's first dynasty, the empire faced a near-constant threat of attack from the nomadic tribes to the north. This included those famed Mongols as well as lesser-known groups like the Xiongnu and the Göktürks.
The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun. Normal warming is mostly caused by natural gases.
Abyssal Plain I think. Sorry if it’s wrong.
Europeans wanted mineral resources! Hopes this helps