Why the Google asks to verify if my device is used by me or a robot whenever I surf too much through Google?

[Piyush]

Today also I surf a lot on internet and then a Google screen appeared saying 'our system recognized unwanted data usage from your device so please verify weather u r a robot or not' and then I have to enter a code which was given above it in a bended manner which only human can understand


same type of verification screen occurs while creating a email account or a Facebook account


I want to know why this happens.
and can robot create a account without any others help or what?

[Linda]

It's a verification procedure. I get that once in a while; nothing to worry about. It just means that there's an increased traffic detected coming from your IP address at one point in time.