How to get an ad's URL?

[MS]

As far as I understand, every Google ad is connected to a URL the Google ad is pointing to.

I've been wading through the Google Ads API documentation for hours by now, but I'm still struggling to get a Google ad's URL using GAQL.

So …

1. What is the GAQL query for retrieving a Google ad's URL?
2. Why is the "final_urls" attribute a collection and not a single string value?
   What's the reason behind this? I've never seen any Google ad pointing to more than a single URL so far.
3. What is the role of asset groups in regard to a Google ad's URL?

Your answer is appreciated.