Open Question: How can I come up with a thesis statement for this essay?

i can write essays pretty well, but i've always been bad at coming up with a thesis statement :( if you could help, that would be really nice. this is what i'm supposed to write my essay on (i need to form a thesis statement that is to be supported by my argument): "EXPLAIN the origins of race-based slavery in the Chesapeake. Was racism a cause or a consequence of slavery?" (fyi: i think it's more of a consequence. i don't think it's a clear-cut answer though) i need to FULLY address the question posed in which my teacher is able to detect the "argument" and can identify the evidence offered in support of my thesis (argument)