16 questions about File uploading and Form handling in PHP programming

1. Do we need to do something specific to do form handling in PHP?
2. How file uploading has to be enabled in a HTML form?
3. How PHP handles file uploading process?
4. What are configuration variables available in PHP for forms?
5. What configuration variables available in PHP for file uploading?
6. What are register_globals in PHP and how these are related to forms?
7. How form data can be accessed in a PHP script?
8. How form data can be secure from bad user inputs?
9. What is the different between move_upload_file function and copy/move function when both can be used in copying/moving uploaded file to a permanent location?
10. How big files upload can be handled in PHP?
11. How we can know the status of file upload progress in middle of an upload?
12. What are common security problems which arise if we enabled the file upload in PHP?
13. How we can prevent security problems associated with file upload in PHP?
14. How form status can be handled in case of multi steps forms?
15. How forms can be submitted to other server/script using PHP script only on server side?
16. How uploaded files can be stored in a databases?