"This country has a lot of gas."
Translation:Ce pays a beaucoup de gaz.
I wasn't sure if the sentence was in US or UK English - previously US English versions have been used e.g. "fall" instead of "autumn". Therefore I thought "gas" was referring to petrol not a gaseous substance, and wrote "beaucoup d'essence". Duolingo, Could you please be clearer about which version of English you are using? Thank you
Il y a means "there is" or "there are". It is an idiomatic expression, and even though it includes avoir, it isn't used to express an idea that can be translated to English using the word "have". Also it includes a subject pronoun, and you don't need a subject pronoun here because the subject is "this country".
If you remember what the other example was, I could try to explain the reasoning behind that one and what the difference is. Or if you come across it again, you can ask about it in the discussion for that sentence.