The central portion of Earth is called the CORE
When the upper water layers warm in the summer months, they become separated from deep water by a transition zone known as a thermocline. In a thermocline, the temperature decreases rapidly with small increases in depth. This phenomenon linking temperature change with depth is called temperature stratification.
<span>On the left, they drain into the renal vein
which in turn drains into the inferior vena cava. By contrast, all the
lumbar veins and hepatic veins usually drain directly into the inferior vena cava.</span>
