What goes up but never comes down?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

what does the below rebus mean?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

It belongs to you, but other people use it more than you do. What is it?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Can you solve the below tricky visual equation?

What is the probability of choosing the correct answer at random from the options below?

a) 1/4
b) 1/2
c) 1
d) 1/4