What is the cause of slaver and the effect for racism. for imperialism

Slavery was caused when europeans went to africa and kidnapped africans into working for them.

Now people know they can't be used to do there laundry without pay, and aren't forced. But, white people are still mad about the fact that they can't have slaves.

a big wall across the mexican border so no drugs, terrorist, or illegal immigrants can come through : )