Answer:
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.
Step-by-step 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.