Question 6 :
What's the difference between include and require?
It's how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.
Question 7 :
How many ways can we get the value of current session id?
session_id() returns the session id for the current session.