Contacts between sedentary and nomad peoples<span> resulted in trade, tribute payments</span>
Answer: The causes of ocean currents include wind, water temperature/salinity and natural disasters.
Explanation:
A current or circulation is the unified movement of water across the ocean. A Surface current affects the topmost layer of seawater and is defined by the direction of the wind while Deep Currents reach the sea floor though a combination of surface currents and landforms.
Water temperature and salinity cause currents by changing water density which in turn results in deep ocean currents circulating the seawater.
Other conditions that cause strong currents are storms and earthquakes which introduces particles into the seawater.
Lack of O2, hunger, hypothermia... Everything can be a problem when in Everest
