Vertical-upstream integration in raw material- energy business..

My essay topic is: What are the pros and cons of upstream-vertical integration in the raw materials / energy business? After describing it, I should do an empirical analysis on a company (or an industry) that has adopted that kind of strategy.
Regardless of which unit of analysis you choose,
make sure that you focus on the specific question you want to address, Make sure you use specific qualitative and/or quantitative evidence to support your argument.
Use appropriate analytical tools (e.g., statistical tools, textual analysis,
If necessary, provide additional analysis in an appendix.