I want a new form or section of questions to pop up if I select a particular Industry or Lead Source. We have different Lead Sources, and they all need to have a different set of questions associated with the Source.

I am trying to add a captcha to my web to lead form in my website to get rid of spam. I haven't found a way that I can get saleforce to recoginze the lead, and for the captcha to work. Any ideas? 

I want a new form or section of questions to pop up if I select a particular Industry or Lead Source. We have different Lead Sources, and they all need to have a different set of questions associated with the Source.