1. If you're going to ask a question, ask only one and then immediately answer it. If it has a long answer (i.e. it introduces a section), then answer it in a way that summarizes the section. Asking a whole bunch of questions at once confuses the reader and wastes her time. It also robs you of authority; the reader might ask "Why is he asking so many questions? Does he not know the answer?"
2. You can also ask several questions to illustrate the extent of the difference of alternatives, alternating between one side and the other. Make sure you summarize at the end, of course. Virigina Postrel does this very well in her book The Future and Its Enemies:
How we feel about the evolving future tells us who we are as individuals and as a civilization: Do we search for stasis--a regulated, engineered world? Or do we embrace dynamism--a world of constant creation, discovery, and competition? Do we value stability and control, or evolution and learning? Do we declare with Appelo that "we're scared of the future" and join Adams in decrying technology as "a killing thing"? Or do we see technology as an expression of human creativity and the future as inviting? Do we think that progress requires a central blueprint, or do we see it as a decentralized, evolutionary process? Do we consider mistakes permanent disasters, or the correctable by-products of experimentation? Do we crave predictability, or relish surprise? These two poles, stasis and dynamism, increasingly define our political, intellectual, and cultural landscape. The central question of our time is what to do about the future. And that question creates a deep divide. (p xiv) [Original Emphasis]