What goes up but never comes down?

What is the below Rebus indicate?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

People make me, save me, change me, raise me. What am I?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

Why do Chinese men eat more rice than Japanese men do ?

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?