Hello. Please help me with grammar.

Question

1)Which is better, one or a: "more than one third of Italy's population" or "more than a third of Italy's population"?
2)Are the phrases correct (meaning "the Italian population"): a third of the (?)Italian people; a third of (the?)Italians?
3)Is it plural or singular: a third of Italian people (Italians) live or lives?
Thank you for help.

Answer 1

In sentences 1 and 2, either phrasing is correct. When you use the word "one," it seems more factual, though, and when you use "a," it seems more casual.

In sentence 3, I'd use the plural.