Answer:
claims of fact, claims of value, and claims of policy
Each type of claim focuses on a different aspect of a topic. To best participate in an argument, it is beneficial to understand the type of claim that is being argued.
The transatlantic slave trade was really a triangle. Here's a map to show the approximate routes. The trade was brought about to benefit the economy of Caribbean nations and Europe. The slaves were forced into awful conditions; cramped boats and harsh climates with which to toil away picking cotton or whatnot.