Removing the security question and adding captcha involves hacking the core which is not advisable as you'll lose changes when you update but if you want to have a look.
/main/controllers/account/Reset.php
/main/views/themes/tastyigniter-orange/account/reset.php
Check how captcha is added to the Registration page here
/main/controllers/account/Register.php
Feel free to ask if you need anything else.