Your professor will discuss what caused people to use social media like Twitter on topics like domestic violence (#whyistayed and #whyileft for example), and #blacklivesmatter and lwhat effects these social media or Twitter chats/engagements had on people and society. See this explanation of a Cause/Effect essay from OWLS and look at the sample paper. Use this cause/effect template to help you organize your essay.
If you are looking for composition books with different types of essays, check out Linda Blanton composition books, particularly, Books 3 and 4. The books provide essay models.