FAQ page, one page or one for each question

Hi!

I'm building a website for a Solar panel and Bioenergy (wood chip-, pellet-, wood-boiler company. The competition have started adding "Frequently asked questions" and I have seen two versions. Either they have all the questions on one page with the question as a title and a hide/show feature. Or they place all the questions after each other and link to a separate page?

What's the best method? Should I have a page for bioenergy questions and one for solar?

Is the hide/show feature damaging SEO? My guess is not because the crawler will see it anyways?

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Thanks for the help!