Why were Africans interested in trading slaves with the Europeans?

Because they got to trade the slaves for items they needed (e.g.) firearms, materials (etc.). So the Europeans didn't have the power to just march in and kidnap Africans to make them slaves, so they provided a trade that would benefit both parties, the Africans got materials they needed and the Europeans got the slaves.

I hope this helps.

the catholic church withhold people's access to the bible during the middle ages.

people could go to church and listen to the teachings, but it was absolutely forbidden to own and/or read the books of both the old and new testaments. it was also prohibited to translate the books (which where originally in biblical hebrew) to any other language.

this was done so the church could remain in control of what their teachings were and to enhance their importance and power, while also being able to judge people's actions through information that was unavailable for the general public.