What does the below rebus riddle means?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

Which digit occurred maximum times between the number 1 and 1000?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

What type of tree can I carry in my hand?

It has horns but can’t beep. It is like to bleat but It is not a sheep. What is it?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Can you name some countries which do not have the alphabet 'A' in them?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain