Europe and America used slaves for labor so the slaves in America or Europe are subtracted from the South African population.
The sighting of a old man, a dead corpse and a diseased man during the time of famine made Gautama sad and this encouraged him to leave the wealth of his palace and lead the life of an ascetic. His departure from home is also known as "The Great Departure". I hope the answer helps you.
Magma in the Earth's mantle moves in convection currents. The hot core heats the material above it, causing it to rise toward the crust, where it cools. The heat comes from the intense pressure on the rock, combined with the energy released from natural radioactive decay of elements.
