Why is my CAPTCHA not fully visible?
If captcha is not showing in that page, then try to change the URL with https or www. In most cases, you will not see the captcha image when loading http version and you need to change the protocol to https to load the image.
What is CAPTCHA validation?
A CAPTCHA test is made up of two simple parts: a randomly generated sequence of letters and/or numbers that appear as a distorted image, and a text box. To pass a the test and prove your human identity, simply type the characters you see in the image into the text box. Why does Google use CAPTCHA?