Where does the money come from Adsense?

As you know, it is possible to earn money with Google Adsense program. Adsense provides ads on your website. If visitors to your website clicks on those ads you earn money. But where does that money come from? That money comes from advertisers. An advertiser may, for example, a shopkeeper who wants to sell its products on its own website. An advertiser can register with the 'brother' of the Adsense program, Adwords. With AdWords, an advertiser can compose their own ads. Google makes sure that ads on the websites come from people who have registered for the Adsense program. For example your website. When someone clicks on this ad, he'll visit the website of the advertiser. And maybe buy a visitor or a product on the website of the advertiser. An advertiser pays for a click so an interested visitor. If you register with Adsense, you earn that money, maybe.