What does this rebus mean?

O
N
C
E
TIME

I’m tall when I’m young, and I’m short when I’m old. What am I?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Why Aeroplane windows are round?

Manish and Manoj play 5 games of chess.
Both Manish and Manoj win the exact same number of games. There is no tie at all.

How?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

Can you identify the Oscar-winning movie from the rebus below?

If eleven plus two equals one, what does nine plus five equal?

Why is 6 afraid of 7?