5. why did the african slave trade increase in the 15th century?

African slave trade increased in the 15th century because colonies were starting to be developed in European countries and there was high demand for labourers to work in their sugar, tobacco and cotton plantations.

Explanation:

African slave trade increased in the 15th century because colonies were starting to be developed in European countries and there was high demand for labourers to work in their sugar, tobacco and cotton plantations. These European countries entered into a relationship with the African countries but this relationship was more beneficial to the Europeans because it caused an increase in their development and wealth creation.

i would think it's industries and hydroelectric power

well that depends on how deep the hole is. you'd first go through te crust of the earth, then the upper mantle, then the lower mantle then the outer core, then the inner cor then you'd be stuck in the core to melt.