Theres a few answrs to this
- It uses your movements before this to determine whether it feels like your a bot or not
- It makes you wait, the biggest issue with bots is they may try to log in say 50 different passwords for example, so if it takes 5 seconds to do each one it makes boting multiple acounts not worth it.
- Google uses catchphas with images to choose. They use this to train their own AI or data to sell
My guess is either your location or notifications. I’m guessing the first assuming the site isn’t just an outright scam.