The part about using real actors and people in simulated performances in movies after they’re dead is the same in holodeck and current cg/ai. Stephen Hawking was used, the real person consented to be on the tv show but the in show historical figure did not.

Replicator food can be identical but it’s also personally tuned for their nutrition and metabolism. The personal replicators and the bigger ones in ten forward aren’t programmed the same.

In the US, marketplace is considered by many to be the only viable in person selling platform since Craigslist is kinda less used now. That’s not counting Whatsapp and the others that fb bought.

Behold, a free book that will give you actual answers. Everyone here is an idiot and will give you wrong advice. Read this instead.

https://openstax.org/books/chemistry-2e/pages/2-6-ionic-and-molecular-compounds