Identify the hidden meaning behind this picture?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

There was a kingdom in which the king had no heir to take over his thrown. Even the queen was dead and he himself was on the verge of dying. He thought about it and then summoned all of the teenagers. He gave one seed each to all of them and asked them to grow the plant. He announced that the one with the most beautiful plant will become the king/queen of the empire after the death of the king.

After a month, all of them were called. The king looked at all of the plants but announced the girl with an empty pot as the queen of the empire. Why?

Can you count the number of blocks in the picture below?

What is the below Rebus indicate?

Write the next letter in this sequence.
O, T, T, F, F, S, S, E, __
**Hint: It is a Number Series Puzzle

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Forwards I am heavy, backward I am not. What am I?