Question

In an explanatory essay, how are body paragraphs related to the introductory paragraph?

Answer 1

In an explanatory essay, or any essay, the introductory paragraph introduces (hence it's name) the main idea, or what you are going to explain. The body paragraphs go into extreme detail of what the introductory paragraphs mentioned. 

Answer 2

The introductory paragraph presents the overall thesis, and each body paragraph focuses on an individual claim.