Language / What does "czy" mean? [37]

So I am learning out of a book and my dad is teaching me at the same time. Im not quite sure what "czy" means. The book says that its a question marker but no idea.

ie. Czy to jest pan Novalski?

Czy to jest żona pan Jacek? Czy to jest bardzo stara ale bardzo ładna?

Those are just a couple of sentences that I put together to demonstrate my understanding of "czy" As you can see, I probably cant use any grammer to save my life but Im trying very hard. I think those sentences are right but please let me know if they are not.

Dziękuję,
ALEX