Q: how can i change my SECURITY QUESTIONS

HT201485

-If you established a rescue email address, there will be a link on the "Passwords & Security" page of id.apple.com.  Clicking the link will send the reset to your rescue email address (NOTE:  This is not the same address as your Apple ID email)

-If there is no link on the page, then you didn't establish a rescue email address.  Contact AppleCare at 800.694.7466 (If you are in the US), and ask for account security.  You will need to answer some questions to verify your identity, AND you will need access to a computer to generate a temporary support pin.

-If you are not in the US, click http://support.apple.com/kb/HT204169 - Apple ID: Contacting Apple for help with Apple ID account security

HTH

The reset link will only show on your account on http://appleid.apple.com if you have a verified rescue email address on it (an additional/alternate email address is different), if you aren't getting the link you will have to contact Support in the country where you are (and which is therefore the country on your account) to get the questions reset : If you forgot the answers to your Apple ID security questions

If you can't reset your security questions

If you can't send a reset email, don't have a rescue email address, or can't access email at your rescue email address, call us for help. When you call, you might need to create a temporary support PIN to verify your identity. After you reset your security questions, you might want to update your rescue email address.

If your country isn't on that ‘call us for help’ page then try this form to contact Support : https://www.apple.com/emea/support/itunes/contact.html