Why did Europeans see Africans as a better source of labor than Native Americans?

Maybe because they knew they were taking the Indian's land so they knew they were going to fight so they had to kill them ... but the blacks who were slaves were sold to Americans so no war or anything happened between them ... they knew the Slaves could not fight and if they did they would still have control

Here's a reason why: Africans were strangers to the Americans. Because the Africans were poor, they didn't have any allies to watch out for them or to protect them.