Explain how tribalism created competition amongst tribes in africa? in other words, how did the slave trade turn into an arms race between tribes, where the best defense was a good offense?

Tribalism refers to human tendency to stay and operate within a social group or a 'Tribe' . This will make us develop a sense of loyalty and protective feeling to the people in our own tribe. But this also make people develop a sense of hostility toward other people from outside their social group.

During the slave trade era, many Tribes in Africa were in conflict with one another due to the competition to obtain resources.

The European Slave traders use this as an opportunity to divide and conquer. So they approached the tribes and promise to give them resources (such as precious metal,crops, or weapons) if they help them capture African natives to be sold as slaves.

Because of this, Tribes in Africa start to attack the members of another tribes, capture them, and give them to the European Slave traders to be sold as slaves. This is what make slave trade turn into an arms race between tribes.

Rather than captured and being sold to slavery, they choose to attack another tribes so they can sold them as slaves instead. In other words, 'best defense was a good offense'